Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports (2010)

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For General Aviation Airport Personnel P A R T 1 Part 1 is intended for GA airport personnel who have day-to-day responsibilities for dealing with hazardous wildlife problems at the airport. It covers the following topics: • Identification, control methods, and legal status of the wildlife species posing the greatest haz- ard to GA aircraft (Chapter 1); • Recognizing hazardous wildlife attractants at or near general aviation airports (Chapter 2); and • Wildlife control strategies and techniques at general aviation airports (Chapter 3).

Introduction Many species of wildlife can pose a direct or indirect threat to aviation safety. However, not all wildlife species are equally hazardous. This chapter discusses the wildlife species posing the greatest threat to aviation safety. Mammals and birds are listed separately, and species within each group are listed alphabetically. Refer to the Ranking Wildlife Species Hazardous to General Aviation Aircraft section of Chapter 4 for a discussion of how the rankings for the various species posing the greatest threats to aviation safety were developed. 9 C H A P T E R 1 The Most Hazardous Species of Wildlife This Learjet 36 struck an elk on departure from Astoria, OR, December 3, 2002. Elk were frequently seen at and around the airport. A 10-ft fence was installed around most of the airport prior to the incident. The airport was seeking permits from the Army Corp of Engineers to allow work in wetlands to complete the fence. The four people on board escaped without injuries. The aircraft cost $5.14 million new in 1997.

The wildlife species listed in Table 4.1 and Figure 7.1 are ranked on the relative “severity of outcome” if they are involved in a strike. Deer, the species having the greatest potential to cause aircraft damage when struck, are ranked highest (100), and all other species are ranked relative to deer. Raptors and vultures are about half as hazardous as deer (half as likely to cause damage), and bats are about one-tenth as hazardous. With the necessary depredation permits in place, shooting problem wildlife is always an option. Anytime wildlife is shot as part of a program to control hazardous wildlife, every effort must be made to retrieve and dispose of dead animals. Federal depredation permits frequent specify the disposal method for federally protected species, generally deep burial or donation to a scientific institution. Only general control methods, specific for each species, are presented in this chapter; detailed discussions of all control methods are presented in Chapter 3. Similar species have been combined into groups (such as all of the gulls, all of the ducks, and all of the deer). Control techniques, legal statuses, and general biology are very similar if not identical for the species within each group. Much of the information presented is adapted from Prevention and Control of Wildlife Damage (Hygnstrom et al. 1994). This publication can be accessed, and articles downloaded free of charge, at icwdm.org/handbook/index.asp. Many of the photos are from the U.S. Fish and Wildlife Service’s National Digital Library found at http://www.fws.gov/digitalmedia. Most Hazardous Mammals Coyotes Control • Mow airside vegetation short to eliminate rabbit and field mouse habitat. • Install 8- to 10-ft chain link fencing with a 4-ft skirt and 3-strand barbed wire outriggers. • Use gas cartridges for den fumigation. • Use leg-hold traps (Nos. 3 or 4) or snares. • Shoot coyotes. 10 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Once limited to the western states, coyotes now range through- out most of North America. [Photo courtesy U.S. Fish and Wildlife Service (U.S. FWS)]

Legal Status Laws regulating coyote control are not uniform among states or even among counties within a state. Contact the state natural resources management agency to determine the coyote’s status and legal take methods. General Biology Coyotes (Canis latrans) often include many items in their diets. Rabbits top the list of their dietary components. Carrion and rodents are also consumed. Coyotes readily eat fruits such as watermelons, berries, and other vegetative matter when they are available. Coyotes are most active at night and during early morning hours (especially where human activity occurs and during hot summer weather). Where there is minimal human interference and during cool weather, they may be active throughout the day. Coyotes bed in sheltered areas but do not generally use dens except when raising young. Their physical abilities include good eyesight and hearing and a keen sense of smell. Documented recoveries from severe injuries are indicative of coyotes’ physical endurance. Although not as fleet as greyhound dogs, coyotes have been measured at speeds of up to 40 miles per hour (64 km/hr) and can sustain slower speeds for long distances. Coyotes usually breed in February and March, producing litters about 9 weeks (60 to 63 days) later in April and May. Average litter size is 5 to 7 pups, although up to 13 in a litter has been reported. More than one litter may be found in a single den; at times these may be from females mated to a single male. Coyotes are capable of hybridizing with dogs and wolves (Green, Henderson, and Collinge 1994). Deer Control • Use pyrotechnics to chase deer away from airports. • Where legal and safe, shoot problem deer at or near airports. • Eliminate all stands of trees and brush in which deer can hide at the airport. • Install 8- to 12-foot chain-link fencing with 3-strand barbed wire outriggers and a 4-foot skirt. This is the best (and most expensive) method for keeping deer away from airports. The Most Hazardous Species of Wildlife 11 Mule deer buck and doe (left); white-tailed deer buck (right). (Photos courtesy U.S. FWS National Digital Library)

Legal Status Deer are protected in all states. Persons wishing to take deer outside of the normal hunting season must have a state depredation permit. Depredation permits are generally issued by the state natural resources management agency. General Biology There are two species of deer in North America: white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus). White-tailed deer are the deer species most commonly struck by aircraft. The white-tailed deer is the most common and widely distributed deer in North America. There are at least 30 recognized subspecies of the white-tailed deer. The peak of breeding season (rut) is generally mid-November. The fawning season is mid-May to late June. Very young females will have only one fawn. However, on good deer range, twins are the rule rather than the exception. Mule deer generally occur in the western half of North America. The breeding and fawning seasons of the mule deer are very similar to that of the white-tailed deer. Single births are most common, and twins are the exception for mule deer. Deer prefer to feed on brush and tender twigs rather than on grass. Dogs Control • Install 8- to 10-foot chain link fencing with a 4-foot skirt and 3-strand barbed wire outriggers. • Use cage traps or steel leg-hold traps (No. 3 or 4). • Shoot feral dogs (where legal and safe). • Use good sanitation, particularly food waste control, around airport. • Do not allow airport employees to feed feral animals. Legal Status State and local laws concerning feral and free-ranging dogs vary considerably, but most states have some regulations. Most cities have animal control agents to pick up abandoned and free- ranging domestic dogs. 12 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports This feral dog, living on a southwestern desert airport, was feeding on food scraps from the airport’s cafeteria and drinking from a broken water line. (Photo E. Cleary)

General Biology Feral dogs (Canis familiaris) are the most widespread of the wild canids. In appearance, most feral dogs are difficult, if not impossible, to distinguish from domestic dogs. Like domestic dogs, feral dogs (sometimes referred to as wild or free-ranging dogs) manifest themselves in a variety of shapes, sizes, colors, and even breeds. The primary feature that distinguishes feral from domestic dogs is the degree of reliance or dependence on humans, and in some respects, their behavior toward people. They are active during dawn, dusk, and at night, much like other wild canids. They often travel in packs or groups and may have rendezvous sites like wolves. Like coyotes, feral dogs will eat almost anything. The only areas that do not appear to be suitable for feral dogs are places where food and escape cover are not available, or where large native carnivores, particularly wolves, are common and prey on dogs (Green and Gipson 1994). Foxes Control • Obstruct foxes with fencing similar to deer fencing. • Exclude the use of frightening tactics as they are generally not effective for foxes. • Use toxicants; the M-44™ is registered for control of red and gray foxes nationwide. • Fumigate fox dens (only in North Dakota, South Dakota, and Nebraska). • Trap foxes using nos. 11⁄2, 13⁄4, and 2 double coil spring traps and nos. 2 and 3 double long spring traps. • Shoot foxes. • Eliminate trees, brush, and other cover within the AOA. • Control rodent prey base on airport property. The Most Hazardous Species of Wildlife 13 The gray fox (left) is slightly smaller than the red fox (right). (Gray fox photo courtesy D. Schaffer/U.S. FWS; red fox photo courtesy J. Thiele/U.S. FWS)

Legal Status In the United States, foxes are listed as furbearers or given some status as game animals by most state governments. Most states allow for the taking of foxes to protect private property. Check with your state wildlife agency for regulations before undertaking fox control measures. General Biology Foxes are most active during the early hours of darkness and the very early hours of the morning. However, they do move about during the day, especially when it is overcast. Foxes are solitary animals except from the winter breeding season through midsummer, when mates and their young associate closely. Foxes are opportunists, feeding mostly on rabbits, mice, bird eggs, insects, and native fruits. Foxes usually kill animals smaller than a rabbit. • The red fox (Vulpes vulpes) is the most common of the foxes native to North America. Except in a few isolated areas, red foxes occur over most of North America, north and east from southern California, Arizona, and central Texas. • Gray foxes (Urocyon cinereoargenteus) are found throughout the eastern, north central, and southwestern United States. They are found throughout Mexico and most of the southwestern United States from California northward through western Oregon. • Kit foxes (V. macrotis) are residents of arid habitats. They are found from extreme southern Oregon and Idaho south along the Baja Peninsula and eastward through southwestern Texas and northern Mexico. • The present range of swift foxes (V. velox) is restricted to the central high plains. They are found in Kansas, the Oklahoma panhandle, New Mexico, Texas, Nebraska, South Dakota, Wyoming, and Colorado. • As its name indicates, the arctic fox (Alopex lagopus) occurs in the arctic regions of North America and was introduced on a number of islands in the Aleutian Islands Chain (Phillips and Schmidt 1994). Raccoons Control • Secure trash cans inside buildings or wire lids down. • Use dumpsters with lids that lock down. 14 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Raccoon. (Photo courtesy D. Menke, U.S. FWS National Digital Library)

• Trap raccoons using no. 1 long spring and no. 11⁄2 coil spring leg-hold traps, 160s through 220s bodygrip traps, and 10 × 12 × 32 (minimum size) single door cage traps. • Shoot raccoons using a .22 caliber rifle or a 16 or 12 gauge shotgun. Legal Status Raccoons (Procyon lotor) are protected furbearers in most states, with seasons established for running, hunting, or trapping. Most states, however, have provisions for landowners to control furbearers that are damaging their property. Check with your state wildlife management agency before using any lethal controls. Many states do not allow live trapping and relocating of raccoons because of the potential spread of rabies. Check with the local game warden or state wildlife management agency before live trapping and relocating raccoons. General Biology Raccoons are found throughout the United States, with the exception of the higher elevations of mountainous regions and some areas of the arid Southwest. Raccoons are more common in the wooded eastern portions of the United States than in the more arid western plains. Raccoons are omnivorous, eating both plant and animal foods. Plant foods include all types of fruits, berries, nuts, acorns, corn, and other types of grain. Animal foods are crayfish, clams, fish, frogs, snails, insects, turtles and their eggs, mice, rabbits, muskrats, and the eggs and young of ground-nesting birds and waterfowl. Contrary to popular myth, raccoons do not always wash their food before eating, although they frequently play with their food in water (Boggess 1994). Most Hazardous Birds American Crows Control • Do not allow cereal grain crops on or near airports. • Thin branches from specific roost trees or thin individual trees from dense groves. • Repel crows using recorded crow distress calls, propane exploders, battery-operated alarms, or pyrotechnics. • Use Avitrol™ (active ingredient: 4-aminopyridine). Birds that ingest Avitrol go into violent distress behavior. One or two reacting birds can frighten many other birds away. • Hunt and shoot crows where legal. • Trap crows with an Australian Crow Trap, a type of decoy trap. Legal Status Crows are protected by the Migratory Bird Treaty Act. However, crows may be controlled without a federal permit when found “committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner to constitute a health hazard or other nuisance” (50 CFR 21.43). States may require permits to control crows and may regulate the method of take. Check with local wildlife officials if there is any doubt regarding legality of control methods. General Biology The American crow (Corvus brachyrhynchos) is one of America’s best known birds. Males and females are outwardly alike. Their large size [17 to 21 in. (43 to 53 cm) long], completely coal-black plumage, and familiar “caw caw” sound make them easy to identify. They are fairly common in areas near people, and tales of their wit and intelligence have been noted in many stories. The Most Hazardous Species of Wildlife 15

Three other crows occur in the continental United States; the fish crow (Corvus ossifragus), the northwestern crow (Corvus caurinus), and the Mexican crow (Corvus imparatus). Fish crows are primarily inhabitants of the eastern and southeastern coastal United States. Fish crows are somewhat smaller than American crows, but in the field they appear much alike. Northwestern crows, as their name implies, occur in the northwest along the coastal strip from Washington to Alaska. They are most often seen foraging along beaches. Northwestern crows are smaller than American crows, but in Washington State these two species may hybridize. Mexican crows occur in south Texas (Brownsville area) primarily during fall and winter and are fairly small for crows. Crows are omnivorous, eating almost anything, and they readily adapt food habits to changing seasons and available food supply. Crows begin nesting in early spring (February to May, with southern nests starting earlier than northern ones) and build a nest of twigs, sticks, and coarse stems. Crow pairs appear to remain together throughout the year, at least in nonmigratory populations, and pairs or pair bonds are likely maintained even within large winter migratory flocks. The average clutch is four to six eggs that hatch in about 18 days. Young fledge in about 30 days. Usually there is one brood per year, but in some southern areas there may be two broods. Both sexes help build the nest and feed the young, and occasionally offspring that are one or more years old (nest associates) help with nesting activities. The female incubates the eggs and is fed during incubation by the male and nest associates. The young leave the nest at about 5 weeks of age and forage with their parents throughout the summer. Later in the year, the family may join other groups that in turn may join still larger groups. The larger groups often migrate in late fall or winter (Johnson 1994). Blackbirds Control • Do not allow cereal grain, corn, and sunflower crops on or near airports. • Repel blackbirds using pyrotechnics, propane cannons, distress calls, electronic noise sys- tems, helium-filled balloons tethered in fields, radio-controlled model planes, reflecting 16 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports American crow. (Photo courtesy U.S. FWS National Digital Library)

tapes made of Mylar, tape-recorded distress calls for birds, various types of scarecrows, and green lasers. • Shoot blackbirds. • Use a toxicant; the only one registered is Starlicide™. • Manage turf grass on airside property as dense monoculture and cut to intermediate heights. • Remove or thin roost trees. Legal Status Blackbirds are protected by the Migratory Bird Treaty Act. However, a federal depredation permit is not needed to take blackbirds when they are found “committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner as to constitute a health hazard or other nuisance” (50 CFR 21.43). Some states have additional restrictions on the killing of blackbirds. General Biology There are about ten species of “blackbirds” in North America. The various species have several traits in common. The males are predominantly black or iridescent in color. All blackbirds have an omnivorous diet consisting primarily of grains, weed seeds, fruits, and insects. The relative proportions of these food groups, however, vary considerably among species. Outside of the nesting season, blackbirds generally feed in flocks and roost at night in congregations varying from a few birds to several million birds. These flocks and roosting congregations are sometimes comprised of a single species, but often several species mix together. Sometimes they are joined by non-blackbird species, notably European starlings (Sturnus vulgaris). Some of the most commonly seen blackbirds include the following: • Red-winged blackbirds (Agelaius phoeniceus) are abundant nesters throughout much of North America. The red-winged blackbird nests in hayfields, marshes, and ditches. Large flocks feed in fields and bottomlands. Redwings winter in the southern United States. • Common grackles (Quiscalus quiscula) are common nesters throughout North America east of the Rockies. Flocks feed in fields, lawns, woodlots, and bottomlands. These birds The Most Hazardous Species of Wildlife 17 Male red-winged blackbird (left), female yellow-headed blackbird feeding young (right). (Photos courtesy U.S. FWS National Digital Library: left, D. Dewhurst; right, P. Norton)

winter in the southern United States, often in association with redwings, cowbirds, and starlings. • Great-tailed grackles (Quiscalus mexicanus) are abundant year-round residents in coastal and southern Texas. The great-tailed grackle nests in colonies in shrubs or trees, sometimes in association with herons and egrets. The flocks feed around farms, pastures, and parks. • Boat-tailed grackles (Quiscalus major) are abundant along the southeastern seaboard, gulf coast, and throughout Florida. They behave similarly and replace the great-tailed grackle in their range. • Brown-headed cowbirds (Molothrus ater) occur in spring and summer throughout much of North America. Flocks feed in pastures and feedlots, and they are often associated with live- stock. Cowbirds winter in the central to southern United States, often roosting with redwings, grackles, and starlings. • Yellow-headed blackbirds (Xanthocephalus xanthocephalus) are locally abundant nesters in deep-water marshes of the northern Great Plains and western North America. They feed in agricultural fields, meadows, and pastures during late summer and fall, sometimes in association with redwings or other blackbirds. They winter farther south than other blackbirds, primarily in Mexico. • Brewer’s blackbirds (Euphagus cyanocephalus) are a familiar bird in the northern Great Plains and western North America. The Brewer’s blackbird nests in a diversity of habitats. It prefers pastures, lawns, and agricultural lands for feeding. It is a winter migrant in the central and southern Great Plains, sometimes roosting with other blackbird species. • Rusty blackbirds (Euphagus carolinus) nest in northern swamps and muskegs (bogs) throughout Canada, Alaska, and northern New England. They migrate in winter to the southern United States from the Atlantic Coast to east Texas. • Tri-colored blackbirds (Agelaius phoeniceus) overlap ranges and may replace red-winged blackbirds in their restricted range primarily in central California. They are abundant in their range, but are afforded much higher protections than redwings and thus care must be taken in identification prior to management strategies being employed (Dolbeer 1994). Cormorants Control • To the extent practicable, eliminate all fish-bearing water at or near airport. • Repel using propane exploders, battery-operated alarms, pyrotechnics, Mylar reflective tape, scarecrows, or Bird Gard Laser™. 18 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Cormorants are fish-eating birds. To the extent practicable, eliminate all fish-bearing water at or near the airport. (Photo courtesy S. Hillebrand, U.S. FWS National Digital Library)

• Place netting over ponds, or install bird balls. • Shoot cormorants. Legal Status Cormorants are protected by the Migratory Bird Treaty Act. This act strictly prohibits the capture, killing, or possession of these birds without a special permit. No permits are required to scare depredating migratory birds except for endangered or threatened species, including bald and golden eagles (50 CFR 21.41). General Biology Cormorants are fish-eating birds that dive from the surface and swim underwater. They often perch with their wings half open to dry. The double crested cormorant (Phalacrocorax auritus) is the most common cormorant in North America. It is the only cormorant that occurs in large numbers inland as well as on both coasts. The sexes are similar in appearance. Adults are entirely black, with small white plumes on their heads during breeding season. Adult cormorants can weigh 4.5 to 5.5 pounds. Cormorant populations have increased tremendously since DDT was banned in the early 1970s. In 1974 there were less than 100 breeding pairs of cormorants on the Great Lakes. Now there are over 120,000 breeding pairs on the Great Lakes, and the population is continuing to increase. In breeding colonies where the nests are placed on the ground, young cormorants leave their nests and congregate in groups with other youngsters (creches). They return to their own nests to be fed. Ducks Control • Repel ducks using pyrotechnics or propane exploders. • Repel ducks using guard dogs. • Repel ducks using scarecrows. • Haze ducks using red or green laser lights. • Repel ducks using chemical repellents such as methyl anthranilate or anthraquinone. (This is very expensive.) • Institute a feeding ban. Feed bans are also better for the waterfowl. • Install overhead wires stretched over water areas. • Install netting over ponds or install bird balls. • Live capture and relocate ducks (easiest late June to late July). • Shoot ducks. • Destroy duck nests and eggs. • Eliminate or minimize water and wetland habitat on airport property. Legal Status All waterfowl are protected by the Migratory Bird Treaty Act. This act strictly prohibits the capture, killing, or possession of these birds. A federal depredation permit and in some cases a state depredation permit is needed before any ducks can be taken. No permits are required to scare depredating migratory birds except for endangered or threatened species, including bald and golden eagles (50 CFR 21.41). General Biology The food of individual waterfowl species ranges from fish to insects to plants, in various combinations, depending on availability. Waterfowl bills have evolved to allow the exploitation The Most Hazardous Species of Wildlife 19

of a wide variety of food sources and associated habitats. Even though many species are adapted to feeding in the water, most will readily come on land to take advantage of available food. Ducks are normally monogamous and solitary nesters. The size of the nesting territory is determined by the aggressiveness of the particular pair of birds. Ducks seek a new mate each year. Studies indicate many species have a first-year mortality rate of 60% to 70% and a 35% to 40% mortality rate in subsequent years. Life spans of 10 to 20 years for captive ducks and 20 to 30 years for captive geese and swans are not uncommon (Cleary 1994). 20 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Top to bottom: American wigeon, mallard duck, northern pintail. (Photos courtesy U.S. FWS National Digital Library; top to bottom: L. Karney, E. and P. Bauer, D. Menke)

European Starlings Control • Repel using pyrotechnics, recorded distress or alarm calls, propane exploders, battery-operated alarms, hawk kites, and Mylar flags. • Use green lasers to help disperse starling roosts. (Starlings do not respond to red lasers.) • Close all hangar openings larger than 1 in. • Install porcupine wires (AKA bird spikes—Nixalite™ and Cat Claw™) to prevent roosting on ledges or roof beams. • Use Avitrol, a restricted-use pesticide that is available in several bait formulations for use as a chemical frightening agent. • Use Roost-No-More™, Bird Tanglefoot™, or 4-The-Birds™ to discourage starlings from roosting on sites such as ledges, roof beams, or airport signs. • Use Starlicide toxicant, which is commercially available as pelletized bait. • Set decoy traps for starlings. • Shoot starlings. • Manage airside turf grass as dense uniform monoculture and cut to intermediate heights. • Remove individual roost trees or trim interior tree branches to eliminate roosting starlings on airport property. Legal Status European starlings (Sturnus vulgaris) are not protected by federal law and in most cases not by state law. However, laws vary among states so check with state wildlife officials before beginning The Most Hazardous Species of Wildlife 21 European starlings were introduced into a park in New York in the 1880s. Today they range throughout the United States. (Photo courtesy D. Menke, U.S. FWS National Digital Library)

a control program. In addition, state or local laws may regulate or prohibit certain control techniques such as shooting or the use of toxicants. General Biology Starlings are robin-sized birds weighing about 3.2 ounces (90 g). Adults are dark with light speckles on the feathers; however, the speckles may not show at a distance. The tail is short, and the wings have a triangular shape when outstretched in flight. Starling flight is direct and swift, not rising and falling like the flight of many blackbirds. The bill of both sexes is yellow during the reproductive cycle (January to June) and dark at other times. Starlings are found in a wide variety of habitats including cities, towns, farms, ranches, open woodlands, fields, and lawns. Ideal nesting habitat includes areas with trees or other structures that have cavities suitable for nesting and short grass (turf) areas or grazed pastures for foraging. Ideal winter habitat includes areas with structures and/or tall trees for daytime loafing (resting) and nighttime roosting. Starlings consume a variety of foods, including fruits and seeds of both wild and cultivated varieties. Insects, especially beetle and butterfly lawn grubs, and other invertebrates total about one-half of the diet overall, and are especially important during the spring breeding season. Other food items—including livestock rations and food in garbage cans—become an important food base for wintering starlings (Johnson and Glahn 1994). Gulls Control • Use pyrotechnics and distress calls to chase gulls away. • Sweep earthworms and other invertebrates from operating surfaces following heavy rains. • Destroy nests and eggs of gulls nesting at or near airport. • Shoot gulls to reinforce repellent effects of pyrotechnics and distress calls. • Display dead gull effigies (lifelike model). • Install wire grids over ponds to stop roosting. • Improve general sanitation at the airport by ensuring proper disposal of all garbage and trash. • Eliminate open garbage dumpsters. • Cut infield turf to intermediate height (6–14 in.). • Eliminate off-airport landfills within designated separation criteria. Legal Status All species of gulls are protected by the Migratory Bird Treaty Act. These laws strictly prohibit the capture, killing, or possession of these birds. Persons wishing to take gulls must obtain a fed- eral depredation permit, and in some cases a state depredation permit. No permits are required to scare depredating migratory birds except for endangered or threatened species, including bald and golden eagles (50 CFR 21.41). General Biology There are about 15 species of gulls regularly found in North America. Gulls are the most fre- quently reported birds struck by civil aircraft in the United States. From 1990 to 2007, about 20% of all identified bird strikes involved gulls. Gulls range in weight from 0.5 pounds for Bonaparte’s gull (Larus philadelphia) to 4 pounds for the great black-backed gull (Larus marinus). The sexes are identical in plumage but males are generally slightly larger than females. Gulls normally nest near water; however, some species will readily nest on rooftops and similar areas. Gulls will eat almost anything. Fish and insects may be the preferred food, but gulls are not averse to dining at the local landfill (Cleary and Dolbeer 2005). 22 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports

Top to bottom: laughing gulls, great black-backed gulls, herring gull, ring-billed gull. (Photos: top and middle courtesy D. Dewhurst, U.S. FWS National Digital Library; bottom courtesy U.S. FWS National Digital Library)

Herons, Egrets, and Cranes Control • Repel using propane exploders, battery-operated alarms, pyrotechnics, Mylar reflective tape, scarecrows, or green lasers. • Eliminate prey species such as field mice and large insects. • To the extent practicable, eliminate all fish-bearing water at or near airport. • Harass with border collies or another suitable type of dog. • Place netting over ponds. • With all necessary federal and state depredation permits in place, shoot herons, egrets, and cranes. Legal Status All herons, egrets, and cranes are protected by the Migratory Bird Treaty Act. This act strictly prohibits the capture, killing, or possession of these birds without a special permit. No permits are required to scare depredating (causing damage) migratory birds except for endangered or threatened species (50 CFR 21.41). However, Florida sandhill cranes (Grus canadensis pratenis) and whooping cranes (Grus americana) are classified as threatened or endangered species. These species may not be harassed without a special permit. General Biology Herons, egrets (Order Ciconiiformes), and cranes (Order Gruiformies) are primarily wading birds and spend much of their time in shallow water hunting for food. They all share certain physical characteristics: extremely long legs and long bills in comparison to the rest of their body. Herons. Herons will normally avoid landing directly in the water to avoid scaring their prey. Instead, they land on the edge and stalk toward the water. These birds prey on a variety of live food such as insects, crustaceans, fish, and amphibians. Generally they are found near wet marshy areas. Great blue herons (Ardea herodias) stand about 70 in. tall and have a 38-in. wingspan. The sexes are similar in appearance. They usually hold their neck in an “S” curve when at rest and in flight. They have a long, thick, yellow bill, and a white crown and face. Egrets. • Great egrets (Ardea alba) have yellow legs and a single head plume coming from behind the eye. They stand about 32 in. tall and have a 55-in. wingspan. This long-legged, long-necked wading bird usually holds its neck in an “S” curve in flight. Its legs are yellow with black feet. The yellow bill is thick and long. Great egrets frequently feed along streams, ponds, rice fields, and saltwater and freshwater marshes. • Snowy egrets (Egretta thula) are smaller than great egrets and have a black bill and yellow feet. They stand about 29 in. tall. Snowy egrets like both freshwater and saltwater marshes and ponds and rice fields for feeding. • Cattle egrets (Bubulcus ibis) are a relatively new emigrant from Africa. They were first sighted in Florida in the late 1950s. Since that time they have spread throughout the United States and Mexico. They are the smallest egret in North America—about 18 to 24 in. tall. They often hunt and feed in agricultural fields and pastures. Items commonly eaten by cattle egrets include small mammals, insects, and amphibians. Cranes. Sandhill cranes (Grus canadensis) are long-legged, long-necked, gray heron-like birds with a patch of bald red skin on top of their heads. They are slightly taller than great egrets. The sandhill crane stands 40 to 45 in. tall with a wingspan of 5 to 7 ft when fully grown. Cranes 24 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports

The Most Hazardous Species of Wildlife 25 Top to bottom: great blue heron, great egret, Florida sandhill cranes. (Photos: top courtesy J. Cossick, U.S. FWS National Digital Library; middle courtesy L. Karney, U.S. FWS National Digital Library; bottom courtesy J. Metcalf, GOAA)

fly with powerful, rhythmic wing beats and necks outstretched like geese, whereas herons fly with necks tucked in on their backs. For positive identification, look for reddish skin on top of the crane’s head. Cranes are quite omnivorous, feeding on seeds, grains, berries, insects, earthworms, mice, small birds, snakes, lizards, frogs, and crayfish. These large birds can be found in both rural and urban areas. The Florida sandhill crane (Grus canadensis pratenis) is a subspecies of the North American sandhill crane. Sandhill cranes will normally mate for life and yearly will lie on or in their nest, which is often on the edge of the water for protection from predators. Mourning Doves Control • Repel doves by using pyrotechnics. • Eliminate feeding, watering, roosting, and nesting sites. • Discourage people from feeding doves. • Exclude doves by using either heavy duty netting or hardware cloth so that birds cannot use the area for nesting or perching. • Clean up spilled grain around grain elevators near airports. • Eliminate pools of standing water that doves use for watering. • Change roost ledges to an angle of 45o or more. • Screen the underside of rafter areas with netting. • Live trap doves. • Shoot doves. • Destroy dove nests and eggs at 2-week intervals. Legal Status Mourning doves are protected by the Migratory Bird Treaty Act. Most if not all states also protect mourning doves. Mourning doves may not be taken outside of the legal hunting season without a federal depredation permit, and in some cases, a state depredation permit. A federal depredation permit is not required to scare depredating migratory birds except for endangered or threatened species, including bald and golden eagles (50 CFR 21.41). General Biology Mourning doves (Zenaida macroura) can cause similar problems to pigeons as they will nest in public structures, underground parking lots, and residential buildings creating the same 26 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Mourning dove. (Photo courtesy D. Menke, U.S. FWS National Digital Library)

unsanitary conditions and damage to property. As they are seed and grain feeders they can cause substantial damage to agricultural crops. Mourning doves are a long, slim, gray-brown bird with a small head and long pointed tail. The dove’s crown, nape, and hind-neck are slate in color, turning grayish, and brown over the rest of the upperparts. They live from southern Canada, throughout the United States, and south to Panama. Mourning doves are found year-round throughout most of their range but northern populations migrate south during the winter. Mourning doves are highly adaptable birds and are found in a wide variety of habitats. They are more common in open woodlands and forest edges near grasslands and fields. They are most abundant in agricultural and suburban areas where humans have created large areas of suitable habitat. The dove is the most widely hunted game bird in North America. Flocks form year round except in breeding season when the birds pair off. Annual adult mortality is about 55%. In the wild the average life span is about 1.5 years. Adult mourning doves weigh between 3.4 to 6 ounces; males are generally larger than females. Female mourning doves generally lay two small, white eggs in an open nest. The young leave the nest about 15 days after hatching but remain nearby until they are more accomplished at flying, usually at about 30 days old. Young are able to breed by 85 days old. Mourning doves have the longest breeding season of all North American birds (Emiley and Dewey 2007; Mirarchi and Baskett 1994). Pigeons Control • Repel pigeons by using pyrotechnics or green lasers. Pigeons show little or no response to red lasers. • Repel pigeons by using chemical repel Avitrol (4-aminopyridine). • Eliminate feeding, watering, roosting, and nesting sites. • Discourage people from feeding pigeons. • Clean up spilled grain around grain elevators near airports. The Most Hazardous Species of Wildlife 27 Rock pigeons were brought to North America by early European settlers for food and to carry messages. Escaped or abandoned birds quickly adapted to conditions in the New World and now can be found in cities and the countryside throughout the Americas. (Photos courtesy USDA)

• Eliminate pools of standing water that pigeons use for watering. • Exclude pigeons from buildings by blocking access to indoor roosts. • Change roost ledges to an angle of 45o or more. • Screen the underside of rafter areas with netting. • Install porcupine wires (Cat Claw, Nixalite™) on flat surfaces wherever pigeons are prone to roost. • Reduce pigeon roosting using various nontoxic chemical repellents (polybutenes) such as 4-The-Birds, Hotfoot™, Bird Tanglefoot, Roost-No-More, and Bird-Proof™. • Use toxicants DRC-1339 (3-chloro-p-toluidine hydrochloride). • Trap pigeons. • Shoot pigeons. • Destroy pigeon nests and eggs at 2-week intervals. Legal Status Feral pigeons (rock pigeons) (Columba livia) are not protected by federal law and most states do not afford them protection. State and local laws should be consulted, however, before any control measures are taken. Some cities are considered bird sanctuaries that provide protection to all species of birds. General Biology Pigeons are found throughout the United States (including Hawaii), southern Canada, and Mexico. Pigeons typically have a gray body with a whitish rump, two black bars on the secondary wing feathers, a broad black band on the tail, and red feet. Body color can vary from gray to white, tan, and black. The average weight is 13 ounces (369 g), and the average length is 11 in. (28 cm). Pigeons are monogamous. Eight to 12 days after mating, the females lay one or two eggs, which hatch after 18 days. The male provides nesting material and guards the female and the nest. The young are fed pigeon milk, a liquid-solid substance secreted in the crop of the adult (both male and female) that is regurgitated. The young leave the nest at 4 to 6 weeks of age. More eggs are laid before the first clutch leaves the nest. Breeding may occur at all seasons, but peak reproduction occurs in the spring and fall. A population of pigeons usually consists of equal numbers of males and females (Williams and Corrigan 1994). Raptors – Hawks, Owls, and Eagles Control • Repel raptors using propane exploders, battery-operated alarms, pyrotechnics, Mylar reflec- tive tape, or scarecrows. • Eliminate perch sites at the airport. • Cap utility poles with sheet metal cones, porcupine wire, or Daddi Long Legs™. • Cut airside grass short to eliminate habitat for rabbits and field mice. • Live trap raptors. • Control rodents and other small mammals at airport to reduce prey base. • Shoot raptors. (You must have a federal depredation permit and, in some cases, a state depre- dation permit.) Legal Status All hawks, owls, and eagles are protected by the Migratory Bird Treaty Act. These laws strictly prohibit the capture, killing, or possession of hawks, owls, or eagles without a special permit. No permits are required to scare depredating migratory birds except for endangered or threatened 28 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports

species, including bald and golden eagles (50 CFR 21.41). Bald and golden eagles may not be harassed without a special permit issued by the U.S. Fish and Wildlife Service. General Biology Hawks, owls, and eagles are birds of prey and are frequently referred to as raptors. Food habits vary greatly among the raptors. Raptors are highly specialized predators that take their place at the top of the food chain. Hawks. There are two main groups of hawks: accipiters and buteos. Accipiters are forest- dwelling hawks. Accipiters are rarely seen except during migration because they inhabit forested areas and are more secretive than many of the buteos. The buteos are known as the broad-winged or soaring hawks. They are the most commonly observed raptors in North America. All buteos have long, broad wings and relatively short, fan- like tails. These features enable them to soar over open country during their daily travels and sea- sonal migrations. The red-tailed hawk (Buteo jamaicensis) is one of our most widely distributed and commonly observed raptors. Red-tailed hawks can be found over the entire North American continent south of the treeless tundra and in much of Central America. Typical eastern red-tailed hawks nest in mature forests and woodlots, while in the Southwest they often nest on cliffs or in trees and cacti. Their diet usually contains large numbers of rodents and other small mammals. Owls. Owls, unlike hawks, are almost entirely nocturnal. Thus, they are far more difficult to observe, and much less is known about them. They have large heads and large, forward-facing eyes. Their flight is described as noiseless and moth-like. There are 19 species of owls in the con- tinental United States. They range in size from the tiny, 5- to 6-in. (12- to 15-cm) elf owl (Micra- thene whitneyi) that resides in the arid Southwest, to the large, 24- to 33-in. (60- to 84-cm) great gray owl (Strix nebulosa) that inhabits the dense boreal forests of Alaska, Canada, and the north- ern United States (Hygnstrom and Craven 1994). Eagles. There are two species of eagles in the United States, bald eagles (Haliaeetus leuco- cephalus) and golden eagles (Aquila chrysaetos). Golden eagles generally hunt small mammals, and bald eagles prefer fish. However, both will readily take whatever is available. In some areas bald eagles are commonly seen feeding at the local garbage dump (O’Gara 1994). The Most Hazardous Species of Wildlife 29 Left to right: peregrine falcon, barn owl, golden eagle. (Photos: peregrine, E. Cleary; owl, C. F. Zeillemaker, U.S. FWS National Digital Library; eagle, G. Gentry, U.S. FWS National Digital Library)

Resident Canada Geese Control • Repel geese using pyrotechnics or propane exploders. • Repel geese using the chemical repellents methyl anthranilate or anthraquinone. • Repel geese using border collies. • Repel geese using scarecrows. • Haze geese with a red or green laser. • Install physical barriers such as wire grids or netting over ponds. • Shoot geese. • Destroy geese nests and eggs. • Live capture and relocate geese (easiest late June to late July). • Eliminate water and wetland vegetation on airport property. • Eliminate agriculture on airport property. Legal Status Resident Canada geese (Branta canadensis) are Canada geese that nest within the lower 48 States in the months of March, April, May, or June, or reside within the lower 48 States and the District of Columbia in the months of April, May, June, July, or August (50 CFR 21.3). Resident Canada geese may be taken within a 3-mile radius of National Plan of Integrated Airport Systems’ airports. Airports and/or their agents must first obtain all necessary authorizations from landowners for all management activities conducted outside the airport’s boundaries, and they must be in compliance with all state and local laws and regulations [50 CFR Part 21.49 d (5)]. Resident Canada geese may be taken between April 1 and September 15. The destruction of resident Canada goose nests and eggs may take place between March 1 and June 30 [50 CFR Part 21.49 d (3)]. General Biology Canada geese are normally monogamous and solitary nesters. Pair formation in geese tends to be permanent until one of the pair dies; the remaining bird will often re-mate. Canada geese lay an egg every other day until the clutch is complete. Incubation is not started until the last or next-to-the-last egg is laid; thus all the eggs hatch at about the same time. Life spans of 20 years for captive geese are not uncommon (Cleary 1994). 30 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports The resident Canada goose population is increasing at about 13% a year. (Photo E. Cleary)

Introduction Land use practices and habitat are the key factors determining the wildlife species and the size of wildlife populations that are attracted to airport environments. The recognition and control of these land use practices and habitats at or near airports that attract hazardous wildlife are fundamental to effective wildlife hazard management plans. The FAA has published a number of Advisory Circulars and CertAlerts that provide guidance to airports certificated under 14 CFR 139 on dealing with management of hazardous wildlife at or near airports. A list of these ACs and CertAlerts can be found in Appendix C, along with Web links to sites where these documents can be read and/or downloaded at no charge. Much 31 C H A P T E R 2 Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports This Beachcraft Baron struck an 80 lb chow dog that ran in front of it during a night departure. The center landing gear collapsed and both propellers struck the ground. (Photo courtesy FAA)

of the material presented in this chapter was derived from these various ACs and CertAlerts. The information contained in them is intended for certificated airports. However, operators of non-certificated airports may find the information useful in dealing with wildlife problems at their airports as well. Through the Grant Assurances, obligated GA airports are required to meet the standards established in some of the ACs. Separation Criteria for Hazardous Wildlife Attractants at or near Airports The minimum separation criteria outlined below are recommended for land use practices that attract hazardous wildlife to the vicinity of airports. Please note that these criteria include land uses that cause movement of hazardous wildlife onto, into, or across the approach or departure airspace, air operation area (AOA), loading ramps (apron areas), or aircraft parking areas of airports. The basis for the separation criteria contained in this section can be found in existing FAA regulations. The separation distances are based on: 1. The flight patterns of piston-powered aircraft and turbine-powered aircraft. 2. The altitude at which most strikes happen (81% occur at under 1,000 ft AGL and 92% occur at under 3,000 ft AGL). 3. National Transportation Safety Board (NTSB) recommendations. The recommended separation distances are diagramed in Figure 2.1. Airports Serving Piston-Powered Aircraft Airports that do not sell Jet-A fuel normally serve piston-powered aircraft. Notwithstanding more stringent requirements for specific land uses, a minimum separation distance of 5,000 ft is recom- mended at these airports for known hazardous wildlife attractants or for new airport development projects meant to accommodate aircraft movement. This distance is to be maintained between an airport’s AOA, loading ramps (apron areas), and aircraft parking areas and the hazardous wildlife attractant. Figure 2.1 depicts this separation distance measured from the nearest AOA. 32 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Landfills that do not accept putrescible waste are not as attrac- tive to birds as those that do. (Photo E. Cleary)

Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 33 PERIMETER A PERIMETER B Apron Parking Area Runway Taxiway Ru nw ay Taxiway PERIMETER C Perimeter A: For airports serving piston-powered aircraft, hazardous wildlife attractants must be 5,000 ft from the nearest air operations area. Perimeter B: For airports serving turbine-powered aircraft, hazardous wildlife attractants must be 10,000 ft from the nearest air operations area. Perimeter C: This is a 5-statute-mile range to protect approach, departure, and circling airspace. Figure 2.1. Separation distances within which hazardous wildlife attractants should be avoided, eliminated, or mitigated. (Diagram taken from FAA AC 5150/5200-33, Hazardous Wildlife Attractants on or near Airports.)

Airports Serving Turbine-Powered Aircraft Airports selling Jet-A fuel normally serve turbine-powered aircraft. Notwithstanding more stringent requirements for specific land uses, a minimum separation distance of 10,000 ft is recommended at these airports for known hazardous wildlife attractants or for new airport development projects meant to accommodate aircraft movement. This distance is to be main- tained between an airport’s AOA, loading ramps (apron areas), and aircraft parking areas and the hazardous wildlife attractant. Figure 2.1 depicts this separation distance measured from the nearest AOA. Protection of Approach or Departure Airspace For all airports, a minimum separation distance of 5 statute miles is recommended between the farthest edge of the airport’s AOA and a known hazardous wildlife attractant if the attractant could cause movement of hazardous wildlife into or across the approach or departure airspace. Figure 2.1 depicts this separation distance measured from the nearest AOA. Land Use Practices That Potentially Attract Hazardous Wildlife The wildlife species and the size of the populations attracted to the airport environment vary considerably, depending on several factors, including land use practices at or near the airport. This section discusses land use practices having the potential to attract hazardous wildlife and threaten aviation safety. Waste Disposal Operations Municipal solid waste landfills (MSWLF) are known to attract large numbers of hazardous wildlife, particularly birds. Because of this, these operations, when located closer than the rec- ommended separation distances (see the previous section entitled “Separation Criteria for Hazardous Wildlife Attractants at or near Airports” and Figure 2.1), are considered incompatible with safe airport operations. 34 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports In the late fall and winter, blackbirds and starlings will form large nighttime roosts. Here over 10,000 blackbirds are roosting near a large southern U.S. airport. (Photo R. Dolbeer)

Siting New Municipal Solid Waste Landfills Do not locate new MSWLFs closer than the recommended separation distances. Measure the separation distances from the closest point of the airport’s AOA to the closest planned MSWLF cell. Considerations for Existing Waste Disposal Facilities within the Limits of Separation Criteria Do not locate airport development projects that would increase the number of aircraft operations or accommodate larger or faster aircraft near MSWLF operations within the sep- aration distances identified in AC 150/5200-33 (see Figure 2.1). In addition, in accordance with 40 CFR 258.10, owners or operators of existing MSWLF units that are closer than the recommended separation distances must demonstrate that the unit is designed and operated in such a way that it does not pose a bird hazard to aircraft. Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 35 Over 3,000 black vultures were counted at this landfill. Many of the birds soared to over 1,500 ft AGL. (Photo E. Cleary) Well over 5,000 gulls were attracted daily to this landfill. In addition, vultures, pigeons, and other birds were also attracted. (Photo courtesy USDA)

To claim successfully that a waste-handling facility sited closer than the recommended sepa- ration distances does not attract hazardous wildlife and does not threaten aviation, the developer must establish convincingly that the facility will not handle putrescible material (organic matter) other than in fully enclosed transfer stations (see the section entitled “Trash Transfer Stations” later in this chapter). In their effort to satisfy the United States Environmental Protection Agency (U.S. EPA) requirement, some putrescible waste facility proponents might offer to undertake experimental measures to demonstrate that their proposed facility will not be a hazard to aircraft. To date, no such facility has been able to demonstrate an ability to reduce and sustain hazardous wildlife to levels that existed before the putrescible waste landfill began operating. For this reason, the FAA does not consider the demonstration of experimental wildlife control at putrescible waste land- fills within the separation distances specified in AC 150/5200-33 to be an acceptable alternative to locating the landfill beyond the separation distances. Trash Transfer Stations Enclosed waste-handling facilities that receive garbage behind closed doors; process it via com- paction, incineration, or a similar manner; and remove all residue by enclosed vehicles generally are compatible with safe airport operations, provided they are not located on airport property or within the runway protection zone (RPZ). Putrescible waste cannot be handled or stored outside or in a partially enclosed structure accessible to hazardous wildlife at these facilities. Trash transfer facilities that leave the main doors open during normal operations, are open on one or more sides, temporar- ily store uncovered quantities of municipal solid waste outside, use semi-trailers that leak or have trash clinging to the outside, or do not control odors by ventilation and filtration systems (odor masking is not acceptable) do not meet the FAA’s definition of fully enclosed trash transfer stations. The FAA considers these facilities incompatible with safe airport operations if they are located closer than the recommended separation distances (see the section entitled “Separation Criteria for Haz- ardous Wildlife Attractants at or near Airports” and Figure 2.1). Composting Operations on or near Airport Property The FAA recommends against locating composting operations on airport property even though composting operations that accept only yard waste (e.g., leaves, lawn clippings, or 36 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Fully enclosed trash transfer stations, such as the one shown here, generally do not attract birds. (Photo courtesy USDA)

branches) generally do not attract hazardous wildlife. Sewage sludge, woodchips, and similar material are not municipal solid wastes and may be used as compost bulking agents. The com- post, however, must never include food or other municipal solid waste. Do not locate compost- ing operations that are off of airport property closer than the greater of the following distances: 1,200 ft from any AOA, loading ramp (apron areas), or aircraft parking space, or the distance called for by airport design requirements (see AC 150/5300-13, Airport Design). This spacing is meant to prevent material, personnel, or equipment from penetrating any object free area (OFA), obstacle free zone (OFZ), threshold siting surface (TSS), or clearway. Monitor compost- ing operations located in proximity to the airport to ensure that steam or thermal rise does not adversely affect air traffic. On-airport disposal of compost by-products is not recommended. Underwater Waste Discharges The underwater discharge of any food waste (e.g., fish processing offal) closer than the rec- ommended separation distances (see the section entitled “Separation Criteria for Hazardous Wildlife Attractants at or near Airports” and Figure 2.1) is not recommended because it could attract scavenging hazardous wildlife. Recycling Centers In most cases, recycling centers that accept previously sorted nonfood items, such as glass, newspaper, cardboard, or aluminum, are not attractive to hazardous wildlife and are acceptable. Construction and Demolition Debris Facilities Construction and demolition (C&D) debris landfills do not generally attract hazardous wildlife and are acceptable if they are maintained in an orderly manner, they admit no putresci- ble waste, and they are not co-located with putrescible waste disposal operations. C&D landfills have similar visual and operational characteristics to putrescible waste disposal sites. When co- located with putrescible waste disposal operations, C&D landfills are more likely to attract haz- ardous wildlife because of the similarities between these disposal facilities. Site C&D landfills co-located with putrescible waste disposal operations outside of the recommended separation distances (see the section entitled “Separation Criteria for Hazardous Wildlife Attractants at or near Airports” and Figure 2.1). Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 37 Composting operations that do not accept putrescible waste generally will not attract birds. (Photo E. Cleary)

Fly Ash Disposal The incinerated residue from resource recovery power/heat-generating facilities that are fired by municipal solid waste, coal, or wood is generally not a wildlife attractant because it no longer contains putrescible material. Landfills accepting only fly ash are generally not considered to be wildlife attractants and are acceptable as long as they are maintained in an orderly manner, they admit no putrescible waste of any kind, and they are not co-located with disposal operations that attract hazardous wildlife. Since varying degrees of waste consumption are associated with general incineration (not resource recovery power/heat-generating facilities), the FAA considers the ash from general incinerators a regular waste disposal by-product and, therefore, a hazardous wildlife attractant if disposed of closer than the recommended separation distances. Water Management Facilities Drinking water intake and treatment facilities, storm water and wastewater treatment facili- ties, associated retention and settling ponds, ponds built for recreational use, and ponds that result from mining activities often attract large numbers of potentially hazardous wildlife. To prevent wildlife hazards, land use developers and airport operators might need to develop man- agement plans, in compliance with local and state regulations, to support the operation of storm water management facilities on or near public-use airports to ensure a safe airport environment. Existing Storm Water Management Facilities On-airport storm water management facilities allow the quick removal of surface water, including discharges related to aircraft deicing, from impervious surfaces such as pavement and terminal/hangar building roofs. Existing on-airport detention ponds collect storm water, pro- tect water quality, and control runoff. Because they slowly release water after storms, they create standing bodies of water that can attract hazardous wildlife [14 CFR 139.337(a)]. Using appro- priate wildlife hazard mitigation techniques, airport management should take immediate cor- rective actions to address any wildlife hazards arising from existing storm water or other such 38 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Trash collection stations, if clean and well maintained, generally do not attract hazardous wildlife. (Photo E. Cleary)

Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 39 Storm water detention basins should be designed to drain completely within 48 hours following the design storm. See next photo. (Photo courtesy USDA) This is the storm water detention pond shown in the previous photo, almost completely drained following an early spring rainstorm. (Photo courtesy USDA) facilities located on or near an airport. In consultation with a qualified airport wildlife biologist, airport management should develop measures to minimize attraction of hazardous wildlife. The FAA established the standards for a qualified airport wildlife biologist in 2007. These qualifica- tions are published in AC 150/5200-36. Where possible, modify storm water detention ponds to allow a maximum 48-hour detention period for the design storm. Avoid the use of or remove retention ponds and detention ponds featuring long-term storage to eliminate standing water. Design or modify detention basins to remain totally dry between rainfalls. Where constant flow of water is anticipated through the basin, or where any portion of the basin bottom may remain wet, include a concrete or paved channel or gravel lined ditch/swale in the bottom to prevent vegetation that may provide cover and food for wildlife.

When it is not possible to drain a large detention pond completely, use physical barriers, such as bird balls, wire grids, pillows, or netting, to deter birds and other hazardous wildlife. When physical barriers are used, carefully evaluate their use and ensure that they will not adversely affect water rescue. Before installing any physical barriers over detention ponds on Part 139 cer- tificated airports, obtain approval from the appropriate FAA Regional Airports Division Office. Encourage off-airport storm water treatment facility operators to incorporate appropriate wildlife hazard mitigation techniques into storm water treatment facility operating practices when their facility is closer than the recommended separation distances (see the section entitled “Separation Criteria for Hazardous Wildlife Attractants at or near Airports” and Figure 2.1). New Storm Water Management Facilities Design and operate off-airport storm water management systems located closer than the rec- ommended separation distances so as not to create aboveground standing water. Design, con- struct, and maintain on-airport storm water detention ponds for a maximum 48-hour detention period for the design storm so the ponds remain completely dry between storms. Use steep- 40 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Bird balls in use near an airport. (Photo J. Allan, Central Science Laboratory, UK)

sided, narrow, linearly shaped water detention basins to facilitate the control of hazardous wildlife. When it is not possible to place these ponds away from the AOA, use physical barriers, such as bird balls, wire grids, pillows, or netting, to prevent access of hazardous wildlife to open water and minimize aircraft-wildlife interactions (refer to Chapter 3 for a discussion of these methods). When using physical barriers, ensure that they will not adversely affect water rescue. States or local jurisdictions may have regulations governing the installation of some types of physical barriers on wetlands. Eliminate all vegetation in or around detention basins that pro- vides food or cover for hazardous wildlife. If soil conditions and other requirements allow, use underground storm water infiltration systems, such as French drains or buried rock fields, because they are less attractive to wildlife. Existing Wastewater Treatment Facilities Immediately correct any wildlife hazards arising from existing wastewater treatment or simi- lar facilities located at or near the airport (14 CFR 139.337). Encourage wastewater treatment facility operators to incorporate measures developed in consultation with a qualified airport wildlife biologist to minimize hazardous wildlife attractants. Encourage wastewater treatment facility operators to incorporate these mitigation techniques into their standard operating prac- tices. In addition, consider the existence of wastewater treatment facilities when evaluating pro- posed sites for new airport development projects and avoid such sites when practicable. New Wastewater Treatment Facilities Do not construct new wastewater treatment facilities or associated settling ponds closer than the recommended separation distances (see the section entitled “Separation Criteria for Haz- ardous Wildlife Attractants at or near Airports” and Figure 2.1). Consider the potential to attract hazardous wildlife during the site location analysis for wastewater treatment facilities if an air- port is in the vicinity of the proposed site. Work with local governing bodies and zoning boards to oppose such facilities if they are closer than the recommended separation distances. Artificial Marshes In warmer climates, wastewater treatment facilities sometimes employ artificial marshes and use submergent and emergent aquatic vegetation as natural filters. These artificial marshes may be used by various species of birds, such as blackbirds and waterfowl, for nesting, feeding, or roosting. Do not establish artificial marshes closer than the recommended separation distances. Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 41 Over 10,000 cattle egrets were seen around this wastewater treatment facility. (Photo E. Cleary)

Wastewater Discharge and Sludge Disposal Do not discharge wastewater or sludge on airport property because it may improve soil moisture and quality on unpaved areas and lead to improved turf growth that can be an attractive food source for many species of grazing animals such as deer and geese. Also, the turf requires more frequent mowing, which in turn might mutilate or flush insects or small animals and produce thatch, both of which can attract hazardous wildlife. Problems might also occur when discharges saturate unpaved airport areas. The resultant soft, muddy condi- tions can severely restrict or prevent emergency vehicles from reaching accident sites in a timely manner. 42 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Before starting any wetland modification project, contact the state department responsible for environmental issues (such as DEQ, DEP, or DNR) to obtain guid- ance on wetland classifications, mitigation and wetland fill permitting require- ments, and mitigation banking opportunities. Wetlands Wetlands provide a variety of functions and can be regulated by local, state, and federal laws. Wetlands typically attract diverse species of wildlife, including many that rank high on the list of hazardous wildlife species (Figure 7.1). If questions exist as to whether an area qualifies as a wetland, contact the local division of the U.S. Army Corps of Engineers, the Natural Resources Conservation Service, or a wetland consult- ant qualified to delineate wetlands. A Memorandum of Agreement (MOA) among six federal agencies was signed in 2003 to facilitate, among other things, resolution of wetland management issues at airports without compromising aviation safety related to wildlife hazards. A copy of the MOA can be downloaded at http://wildlife-mitigation.tc.faa.gov/public_html/index.html. This wetland is less than 500 ft from a major airport runway. A Canada goose nest is situated at the base of the middle large tree. (Photo E. Cleary)

Existing Wetlands on or near Airport Property If wetlands are located on or near airport property, be alert to any wildlife use or habitat changes in these areas that could affect safe aircraft operations. Working in cooperation with local, state, and federal regulatory agencies, airports should immediately correct any wildlife haz- ards arising from existing wetlands located at or near airports. Develop measures to minimize attraction of hazardous wildlife in consultation with a qualified airport wildlife biologist (AC 150/5200-36). New Airport Development Whenever possible, locate new airports using the separation criteria from wetlands identified in AC 150/5200-33 (see Figure 2.1). Where alternative sites are not practicable, or when expand- ing an existing airport into or near wetlands, in consultation with a qualified airport wildlife biol- ogist, the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, and the state wildlife management agency, evaluate the wildlife hazards and develop a plan for eliminating or mini- mizing the hazards. Mitigation for Wetland Impacts from Airport Projects Wetland mitigation might be necessary when wetland disturbances result from new airport development projects or projects required to correct wildlife hazards from wetlands. Wetland mitigation must be designed so it does not create a wildlife hazard. Locate wetland mitigation projects that may attract hazardous wildlife outside of the separation criteria identified in AC 150/5200-33 (Figure 2.1). On-Site Mitigation of Wetland Functions The FAA may consider exceptions to locating mitigation activities outside the separation crite- ria identified in AC 150/5200-33 if the affected wetlands provide unique ecological functions, such as critical habitat for threatened or endangered species or for groundwater recharge, which cannot be replicated when moved to a different location. Using existing airport property is sometimes the Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 43 This mitigation site on a large western airport creates habitat for an endangered species. However, it also attracts waterfowl and other birds that pose a threat to aircraft safety. (Photo courtesy USDA)

only feasible way to achieve the mitigation ratios mandated in regulatory orders and settlement agreements with the resource agencies. Conservation easements are an additional means of pro- viding mitigation for project impacts. Mitigation must not inhibit the airport operator’s ability to effectively control hazardous wildlife on or near the mitigation site or effectively maintain other aspects of safe airport oper- ations. Avoid enhancing such mitigation areas to attract hazardous wildlife. A qualified airport wildlife biologist should review any onsite mitigation proposals to determine compatibility with safe airport operations. In cooperation with a qualified airport wildlife biologist, evaluate any wetland mitigation projects that are needed to protect unique wetland functions and that must be located in the separation criteria in AC 150/5200-33 before the mitigation is implemented. Develop a wildlife hazard management plan (WHMP) to reduce any identified wildlife hazards. (Also see CertAlert 06-07 regarding state-listed threatened and endangered species.) Off-Site Mitigation of Wetland Functions Site wetland mitigation projects that might attract hazardous wildlife outside of the separa- tion criteria identified in AC 150/5200-33 unless they provide unique functions that must remain on site [AC 150/5200-33, § 2-4c(1)]. Agencies that regulate impacts to or around wetlands rec- ognize that it may be necessary to split wetland functions in mitigation schemes. Therefore, reg- ulatory agencies may, under certain circumstances, allow portions of mitigation to take place in different locations. Mitigation Banking Wetland mitigation banking is the creation or restoration of wetlands in order to provide mit- igation credits that can be used to offset permitted wetland losses. Mitigation banking benefits wetland resources by providing advance replacement for permitted wetland losses; consolidat- ing small projects into larger, better-designed and managed units; and encouraging integration of wetland mitigation projects with watershed planning. This last benefit is most helpful for air- port projects because wetland impacts mitigated outside of the separation criteria identified in AC 150/5200-33 can still be located within the same watershed. Wetland mitigation banks meet- ing the separation criteria offer an ecologically sound approach to mitigation in these situations. 44 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports This Army Corps of Engineers wetland mitigation site is adjacent to taxiways and runways on a major U.S. airport. Airport opera- tors should actively oppose locating mitigation sites next to airports. (Photo courtesy USDA)

Working with local watershed management agencies or organizations, develop mitigation bank- ing for wetland impacts on airport property. Dredge Spoil Containment Areas Do not locate dredge spoil containment areas (also known as confined disposal facilities) within the separation criteria identified in AC 150/5200-33 if the containment area has standing water or the spoils contain material that would attract hazardous wildlife. Agricultural Activity Most, if not all, agricultural crops can attract hazardous wildlife during some phase of pro- duction. Do not use airport property for crop production, including hay crops, within the sep- aration criteria identified in AC 150/5200-33. Crop Production If the airport has no financial alternative to agricultural crops to produce income necessary to maintain the viability of the airport, then the airport must follow the crop distance guidelines listed in the table titled “Minimum Distances between Certain Airport Features and Any On-Airport Agricultural Crops” found in AC 150/5300-13, Airport Design. Avoid production of cereal grains and sunflowers. Weigh the cost of wildlife control and potential accidents against the income pro- duced by the on-airport crops when deciding whether to allow crops on the airport. Livestock Production Confined livestock operations (i.e., feedlots, dairy operations, hog or chicken production facil- ities, or egg-laying operations) often attract flocking birds, such as starlings, that pose a hazard to aviation. Therefore, keep such facilities outside of the separation criteria identified in AC Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 45 When this Army Corps of Engineers dredge spoil containment area (right) first opened, over 20,000 Bonaparte’s gulls wintered on it. The runway of a midwestern airport (left) is less than 100 ft from the containment area. (Photo E. Cleary)

150/5200-33. Develop a program to reduce the attractiveness of any livestock operation within these separation distances. Do not graze free-ranging livestock on airport property because the animals might wander onto the AOA. Livestock feed, water, and manure might also attract haz- ardous wildlife. Aquaculture Aquaculture activities (such as catfish, trout, and bait fish production) conducted outside of fully enclosed buildings are inherently attractive to a variety of birds. Existing aquaculture facilities/ activities within the separation criteria listed in AC 150/5200-33 must have a program developed to reduce the attractiveness of the sites to species that are hazardous to aviation safety. Oppose the establishment of new aquaculture facilities/activities within the separation criteria listed in AC 150/5200-33. Alternative Uses of Agricultural Land Some airports are surrounded by vast areas of farmed land within the distances specified in AC 150/5200-33. Seasonal uses of these agricultural lands for activities such as waterfowl hunt- ing can create a hazardous wildlife situation. Rice farmers, for example, might flood their land during waterfowl hunting season and obtain additional revenue by renting out duck blinds. The duck hunters, using decoys and calls, draw in large numbers of birds, creating a threat to aircraft safety. It is recommended that a qualified airport wildlife biologist review, in coordination with local farmers and airport management, these types of seasonal land uses. Restrictions to seasonal land uses that are incompatible with aviation safety should be incorporated into the WHMP. Airside Vegetation Management Managing the airside vegetation to minimize the area’s attractiveness to hazardous wildlife is the best way of reducing the strike risk at an airport. Properly managed turf grass can be highly effective in deterring a variety of hazardous wildlife species. Research conducted by the U.S. Department of Agriculture–Wildlife Services (USDA/WS) National Wildlife Research Center has shown that no one grass management regime will deter all species of hazardous wildlife in 46 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Hundreds of pigeons were attracted to this cattle feedlot. Feed- lots should be outside the recommended separation distances. (Photo courtesy U.S. FWS)

all situations. Since airports rarely deal with only one species of hazardous wildlife, a compro- mise regime to affect the collective majority of species is necessary. Managing for only one species will generally cause other species to be attracted in its place. Research from around the world has shown that a dense, uniform stand of grass without broad-leaved weedy vegetation or openings will effectively deter the majority of species since most wildlife cannot digest grass or subsist on a grass diet. (However, there are exceptions such as geese.) In addition to maintaining turf grass, the height of the grass is important to further deter birds and other wildlife, especially flocking species. Intermediate height is recommended and generally should be maintained between 6 and 12 in. The Department of Defense has conducted numerous studies on several continents and most of the United States and mandates that grass be maintained between 7 and 14 in. to Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 47 A mix of grass, brush, and trees provide near ideal habitat for many birds and mammals that can pose a threat to aircraft. Whenever possible, manage the airside vegetation to eliminate all brush and trees. (Photo E. Cleary) Do not landscape airports with plants that produce fruits, nuts, or berries. The berries on these bushes are highly attractive to cedar waxwings and other small birds. (Photo R. Dolbeer)

accomplish these goals. Such research has found that flocking bird species are effectively deterred because the intermediate height: • Disrupts visual communication systems; • Prevents predator detection; • Obscures invertebrate food sources in the soil and on vegetation; • Requires additional energy expenditure for movement; • Limits weed growth; and • Slows vegetative growth rates. It is important to recognize that the intermediate height recommendation encompasses a range, as some species will begin to seed below the upper threshold and should be mown before seed head development. Seeds will attract birds, rodents, and other animals and if the vegetation becomes too tall, mower operation becomes difficult and other vegetation may begin to encroach on turf grasses. The intermediate turf height should be maintained over the entire infield, includ- ing to the edges of operating surfaces. Elevated lights and signs can remain visible above the lower threshold of recommended grass height, and airports should not mow the edges of these surfaces at lower standards as hazardous wildlife can be attracted to the most vulnerable areas of the field if shorter grass is supported along these surfaces. In cooperation with a qualified airport wildlife biologist, develop airport turf grass manage- ment plans and appropriate seed mixtures to meet the objective of uniform turf species at proper heights and adapted to the local environment and climate conditions. Ensure that plant varieties attractive to hazardous wildlife are not used on the airport. Do not plant disturbed areas or areas in need of re-vegetating with seed mixtures containing millet or any other large-seed producing grass. On airport property already planted with seed mixtures containing millet, rye grass, or other large-seed producing grasses, prevent plant maturation and seed head production by the use of disking, plowing, or another suitable agricultural practice. Follow the specific recommendations for grass management and seed and plant selection made by the state university cooperative extension service, the local office of USDA/WS, or a qualified airport wildlife biologist. In addition, wherever possible, eliminate broad-leaved weeds, brush, 48 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports It is extremely important to keep the airside as unattractive as possible to hazardous wildlife, especially when there are other hazardous wildlife attractants such as lakes and dense vegeta- tion close to the airport. (Photo E. Cleary)

trees, and wetland vegetation anywhere within the AOA to reduce attractiveness to hazardous birds and other wildlife. Some airports exist in areas of the country where turf grasses cannot be supported due to adverse soil or climate conditions, and other vegetation species may be considered. In extreme cases such as desert environments, alternate cover such as sealed gravel may be effective at deter- ring hazardous wildlife species. Where necessary, develop alternate management strategies in cooperation with a qualified airport wildlife biologist. Landscaping, Golf Courses, and Other Land Use Considerations Landscaping and Landscape Maintenance Depending on geographic location and plant selection and spacing, airport landscaping can attract hazardous wildlife. Approach landscaping with caution, and confine it to airport areas not associated with aircraft movements. In cooperation with a qualified airport wildlife biologist review all landscaping plans. Monitor all landscaped areas on a continuing basis for the presence of hazardous wildlife. If hazardous wildlife is detected, take corrective action immediately. Consider developing and implementing a preferred/prohibited plant species list, reviewed by a qualified airport wildlife biologist, which has been designed for the geographic location to reduce the attractiveness to hazardous wildlife for landscaping airport property. Avoid installation of ponds, fountains, reflecting pools, and other water bodies as part of an airport’s landscaping scheme. Golf Courses The large grassy areas and open water found on most golf courses are attractive to hazardous wildlife, particularly Canada geese, mallards, and gulls. These species can pose a threat to aviation safety. Do not site new golf courses within the separation criteria identified in AC 150/5200-33. Existing golf courses located within these separation distances must develop a program to reduce the attractiveness of the sites to species that are hazardous to aviation safety. Ensure that these Recognizing Hazardous Wildlife Attractants at or near General Aviation Airports 49 Golf courses offer resident Canada geese ideal habitat: food, water, and shelter. (Photo courtesy USDA)

golf courses are monitored on a continuing basis for the presence of hazardous wildlife. If haz- ardous wildlife is detected, take corrective action immediately. Other Hazardous Wildlife Attractants Other unique land uses or activities (such as sport or commercial fishing, or shellfish produc- tion and harvesting) have the potential to attract hazardous wildlife. Regardless of the source of the attraction, when hazardous wildlife is noted on a public-use airport, airport operators must take prompt remedial action to protect aviation safety. Synergistic Effects of Surrounding Land Uses There may be circumstances where two or more different land uses that would not, by them- selves, be considered hazardous wildlife attractants or that are located outside of the separation criteria identified in AC 150/5200-33 are in such an alignment with the airport as to create a wildlife corridor directly through the airport and/or surrounding airspace. An example of this situation could involve a lake located outside of the separation criteria on the east side of an air- port and a large hayfield on the west side of an airport—land uses that together could create a flyway for Canada geese directly across the airspace of the airport. There are numerous exam- ples of such situations; therefore, airport operators and the qualified airport wildlife biologist must consider the entire surrounding landscape and community when developing any plan to minimize the hazards. 50 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports These laughing gulls are drinking in a rainwater puddle at a coastal airport’s parking lot. At coastal airports, rainwater puddles may be the only source of fresh water, and as such are highly attractive to birds. (Photo courtesy USDA)

Introduction Wildlife is attracted to an airport because the airport offers something the wildlife wants or needs. Most often the attractants are food, water, or shelter. Therefore, controlling wildlife prob- lems at or near an airport requires carrying out measures to deny wildlife access to the attrac- tants or reducing their availability. Occasionally it may be necessary to reduce or eliminate specific wildlife species or populations to protect aircraft safety. 51 C H A P T E R 3 Wildlife Control Strategies and Techniques at General Aviation Airports Areo County Airport, Frisco, Texas, July 8, 2003. The instructor pilot and student suffered fatal injuries when their aircraft hit what was believed to be a black vulture at 800 ft AGL. (Photo courtesy FAA)

Basic Control Strategies There are five basic strategies airport managers can use to manage hazardous wildlife at or near the airport: • Repelling techniques: Use of various audio, visual, or chemical repellents to harass and repel problem wildlife. • Habitat modification: Elimination or reduction of food, water, or shelter attractive to wildlife at or near the airport. • Exclusion: Use of physical barriers to stop wildlife from gaining access to food, water, or shel- ter at or near the airport. • Population management: Reduction or elimination of wildlife populations that are posing a hazard to aircraft at or near the airport by either capturing (live capture and relocation) or killing the problem animals. • Notices to Airmen (NOTAM) of potential wildlife hazards: Delaying or advancing takeoff and landing times; changing or closure of active runways. The following presents a general discussion of these control strategies that are applicable to both birds and mammals. After that, specific control strategies for birds and mammals are pre- sented. To be effective, airports need to use a combination of control strategies to deal with wildlife, based upon available resources, including funding, staff, and specific wildlife issues. Repelling Techniques Repelling and harassment techniques create psychological barriers by making the area or resource unattractive to wildlife or by making the wildlife uncomfortable or fearful. Long-term, the cost-effectiveness of repelling wildlife usually does not compare favorably with habitat mod- ification or exclusion techniques. No matter how many times wildlife are driven from an area that attracts them, they or other individuals of their species will return as long as the attractant is accessible. However, because habitat modifications and exclusion techniques will not rid an airport of all problem wildlife, repelling techniques are a key part of any GA airport’s control efforts for hazardous wildlife. 52 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Properly installed and maintained fencing will keep most large mammals out of an airport. Places where drains run under the fence should have guards installed to prevent animals from crawling under the fence. (Photo E. Cleary)

Repellents work by affecting the animal’s senses through chemical, auditory, or visual means. When used repeatedly without added reinforcement, wildlife soon learn that the repellent devices or techniques are harmless. The devices become a part of the “background noise,” and wildlife ignore them. Habituation of birds and mammals to most repellent devices or techniques is a major problem. When using repellents, recognize these critical facts: 1. There are no “silver bullets” that will solve all problems. Airport managers will need to imple- ment adaptive control strategies to address the ever-changing threat and risk levels. 2. There is no standard protocol or set of procedures that is best for all situations. Repelling wildlife is an art as much as a science. To be successful, employ motivated, trained, and prop- erly equipped personnel who understand the wildlife situation at their airport. 3. Each wildlife species is unique and will often respond differently to various repellent tech- niques. Even within a group of closely related species, such as gulls, the various species will often respond differently to various repellent techniques. 4. Minimize habituation to repellent techniques by using each technique sparingly and correctly when the target wildlife is present, by using various repellent techniques in an integrated fash- ion, and by reinforcing repellents with occasional lethal control (with necessary permits in place) directed at plentiful problem species such as gulls or geese. Habitat Modification Habitat modification means changing the environment to make it less attractive to the prob- lem wildlife. All wildlife require food, water, and shelter to survive. Any action that reduces or removes one or more of these elements will result in a proportionate reduction in wildlife pop- ulation. Habitat modifications to make the airport and surrounding area as unattractive as pos- sible to hazardous wildlife must be the foundation of every GA airport’s effort to deal with wildlife problems. Initially, management actions to reduce or remove food, water, and shelter from an airport might be expensive. However, when costs are spread over several years, these actions could be Wildlife Control Strategies and Techniques at General Aviation Airports 53 Dead bird effigies have proven effective repellents. Remember, depredation permits must be in place before state or feder- ally protected birds can be obtained and used as bird deter- rents. (Photo T. Seamans)

the least expensive approach to reducing wildlife populations at the airport. Once a habitat mod- ification is done correctly, it should not be necessary to go back and do it again. Also, these con- trol methods are well accepted by the public and lessen the need to harass or use lethal control. Some habitat modification projects, such as draining wetlands, may require a permit from either the state department of environmental protection or the U.S. Army Corps of Engineers. Refer to the Chapter 2 section “Mitigation for Wetland Impacts from Airport Projects” for a more detailed discussion of wetland mitigation. Exclusion Techniques When food, water, or shelter cannot be removed by habitat modification, then try to exclude the wildlife from the desired resource. Exclusion involves the use of physical barriers—screening, netting, and grid wires—to deny wildlife access to a particular area. As with habitat modifica- tion, exclusion techniques, such as installing a covered drainage ditch instead of an open ditch, can initially be costly. However, exclusion provides a permanent solution that is environmen- tally friendly, and when amortized over many years, the cost is relatively inexpensive. Population Management Techniques As previously indicated, repellent techniques, habitat modification, and exclusion are the first lines of action in any GA airport’s effort to address problem wildlife. However, these actions will not solve every problem; therefore, hazardous wildlife sometimes must be removed from an airport. Remove hazardous wildlife by lethal means or by capturing and relocating the target animals. 54 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports This ultrasonic sound generator is not effective. The gulls are using it as a perch and to keep their feet warm. (Photo R. Dolbeer)

Caution: • With few exceptions, a federal Migratory Bird Depredation Permit, and often a state per- mit, is required before taking any migratory birds. As used here, “taking” means either “to capture or kill” or “to attempt to capture or kill” a migratory bird. • A state permit is necessary before taking any state-protected birds or mammals. • Any capturing or killing must be done humanely and only by people who are trained in identification of wildlife species and appropriate techniques for taking. The management of wildlife problems at GA airports often generates interest from the public and news media, especially when lethal control methods are to be used. GA airport managers and public relations personnel, employed by the airport or airport sponsor, must be prepared to explain and defend actions taken to protect the flying public from wildlife hazards. If necessary, Wildlife Control Strategies and Techniques at General Aviation Airports 55 Plastic strips were hung over this drain to stop swallows form nesting in it. (Photo P. Robinson) Removal of problem wildlife is often necessary as part of an overall wildlife hazard management program. This hawk, cap- tured at a large airport, will be relocated. (Photo courtesy USDA)

GA airport managers can, and should, seek help from qualified airport wildlife biologists when dealing with the news media on this subject. Notices to Airmen of Potential Wildlife Hazards Pilots are the final decision makers as to whether or not to take off or land. They need up-to- date information concerning potentially hazardous conditions at or near the airport to intelli- gently make such decisions. Airport managers have a responsibility to advise pilots of potentially hazardous situations, through NOTAMs or other normal channels. At controlled airports, air traffic control (ATC) personnel have a responsibility to notify pilots of any known hazards, including wildlife at or near the airport. Strategies and Techniques for Controlling Birds Repelling Techniques Repelling problem wildlife involves the use of various audio, visual, or chemical tools designed to make the wildlife feel uncomfortable, apprehensive, or fearful so that they will leave the area. Because most repellents are not lethal, wildlife will quickly habituate to them if they are used repeatedly without occasional lethal reinforcement. Audio Repellents Pyrotechnics. There are various projectiles that can be fired from breech-loaded shotguns or from specialized launchers to provide an auditory blast or scream, as well as smoke and flashing light, to frighten birds. Some of the newer cartridges have ranges of up to 300 yards. These pyrotechnics, when used skillfully in combination with other harassment techniques and limited lethal control (shooting with shotgun), can be useful in driving birds away from an airport. An advantage of these pyrotechnic devices is that they require a person to fire the projectile, thus ensuring that they are used on the target birds, and the birds associate the pyrotechnic with a threat (person). 56 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports This Navy T-44 trainer struck a turkey vulture while conducting low-level training exercises near Corpus Christi, TX. The student pilot was able to land safely.

Propane cannons. Propane cannons (exploders) produce a shotgun-sounding blast. In gen- eral, birds quickly habituate to cannons that detonate at fixed or random intervals throughout the day. Thus, to ensure they remain effective, use cannons sparingly and only when birds are in the area. Reinforcement by targeting common species such as gulls and Canada geese, under author- ity of a suitable depredation permit, and occasionally killing a few birds will improve effectiveness. Systems designed with cannons placed around an airport are a useful means of reducing habitua- tion if they can, on demand by radio signal, be detonated remotely when birds are in the area. Distress call and electronic noise-generating systems. Recorded distress calls are available for common birds at airports, such as gulls, crows, and starlings. Such calls, broadcast from speakers mounted on a vehicle, will often initially draw the birds toward the sound source to investigate the threat. Disperse the birds using pyrotechnics or using a shotgun to remove an occasional bird. Without lethal reinforcement, birds will quickly learn that distress calls and other electronic noise-generating devices are harmless and will ignore them. Ultrasonic devices. Ultrasonic (that is, above the sound range detected by humans) devices are not effective bird repellents. Most birds hear in a narrower range of sound frequencies than humans. If a high-frequency sound cannot be heard by humans, chances are good that it cannot be heard by birds either. Use of these devices in hangars or other airport settings to deter birds is not recommended. If the sound pressure is high enough, even if humans cannot hear it, such devices can cause hearing damage to airport personnel and customers. Visual Repellents Most visual repellents are simply a variation on an ancient theme—the scarecrow. In general, visual repellents, such as plastic owls and similar devices, eye-spot balloons, flags, and Mylar reflecting tapes, have shown only short-term effectiveness and are inappropriate for use as a long-term solution to bird problems. Most short-term success achieved with these devices is likely attributable to “new object reaction” rather than to any frightening effect produced by them. For example, in a test in Ohio, researchers exposed a flag with a large eyespot to pigeons in an abandoned building. As soon as the flag was put up, the pigeons left the building, giving the impression the eyespot was repellent to the birds. However, within 24 hours, the pigeons returned. From then on, the pigeons behaved in a normal fashion and showed no interest in, or reaction to, the flag. Wildlife Control Strategies and Techniques at General Aviation Airports 57 All wildlife will quickly habituate to propane cannons and other noise scaring devices if they are used constantly without lethal reinforcement. (Photo E. Cleary)

One visual deterrent successfully used in recent years is displaying dead birds in a “death pose.” Several experiments and field demonstrations have shown that a dead turkey vulture (freeze-dried taxidermy mount with wings spread), hung by its feet in a vulture roosting or perching area, will cause vultures to abandon the site. Early trials using dead gulls and ravens sus- pended from poles have also shown promising results in dispersing these species from feeding and resting sites. Hang the dead bird in a “death pose” to be effective. Dead birds lying supine on the ground or in the roost are ignored and might even attract other birds. Research is under- way to determine if artificial effigies (dead bird models) can be developed that will be just as effec- tive as the taxidermy mounts. Another new idea in visual repellency that has shown utility in recent years is the use of handheld lasers that project a 1-in. diameter red or green beam. These devices have been used successfully to disperse birds such as Canada geese, double-crested cormorants, and crows from nighttime roost- ing areas in reservoirs and trees. Advantages include effectiveness at long ranges (over 1⁄4 mile) and lack of noise. Lasers have also shown some effectiveness in dispersing birds from hangars. Lasers are not effective in full sun conditions but are very effective at night and during overcast cloudy condi- tions. Personnel using lasers in an airport environment should be trained in the safe use of lasers and should coordinate their activity with ATC and airport management. Chemical Repellents Chemical repellents, toxicants, and capturing agents must be registered with the U.S. EPA or U.S. Food and Drug Administration (FDA) before being used to manage wildlife at airports. Prod- ucts must also be registered in each state. The chemical repellents discussed below are available for use at airports (as of 2009). A more detailed discussion of these and other chemicals for use in controlling airport wildlife can be found in Prevention and Control of Wildlife Damage (Hygn- strom et al. 1994). This handbook is available on the web at icwdm.org/handbook/index.asp. Perching structures (polybutenes). Several commercial anti-perching products are available in liquid or paste form. These sticky formulations make birds uncomfortable when they alight on them, encouraging the birds to look elsewhere to perch or roost. To be effective, treat all perching 58 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Under low light conditions, specially designed lasers can be effective in repelling geese, cormorants, and other birds. (Photo courtesy USDA)

Wildlife Control Strategies and Techniques at General Aviation Airports 59 Left: A technician applies anti-perching paste to a building ledge to stop birds from roosting on it. Right: The anti-perching paste was applied over duct tape to facilitate cleanup. (Photos: left courtesy Bird Proof®, right E. Cleary) A methyl anthranilate formulation is available for use in fogging machines (thermal or mechanical) to disperse birds from hangars, lawns, and other areas. (Photo courtesy USDA) surfaces in a problem area or the birds will move a short distance to an untreated surface. Under normal conditions, the effective life of these materials is 6 months to 1 year. Dusty environments can substantially reduce the life expectancy. Use in high temperatures also causes material to become more fluid and run off surfaces and can be extremely difficult to clean. Once the material loses effectiveness, it is necessary to remove the old material and apply a fresh coat. Applying the material over duct tape, rather than directly to the building ledge or rafter surface, will ease cleanup. Turf feeding (anthraquinone, methyl anthranilate). There are two chemicals registered (2008) as bird repellents for turf (grass). Anthraquinone is registered for repelling geese from turf. Anthraquinone seemingly acts as a conditioned-aversion repellent with birds. Birds eating food treated with anthraquinone become slightly ill and develop a post-ingestion aversion to the treated food source. Birds visually iden- tify anthraquinone in ultraviolet light (which they can see) and become conditioned to avoid the treated food source. Because of its conditioned-aversion properties, anthraquinone use does not require treatment of the entire airfield, but only areas where birds are grazing and/or higher risk

areas such as runway approaches. However, due to large areas that may require coverage at air- ports, and the non-persistent nature of the chemicals, these techniques can be very costly. Methyl anthranilate is a commercial grade artificial grape flavoring commonly used in foods and drinks. Birds have a taste aversion to methyl anthranilate, seemingly reacting to it in much the same way that mammals react to concentrated ammonia (smelling salts). Methyl anthrani- late is registered as a feeding repellent for geese and other birds on turf. Again, because of the non-persistence of this chemical and the large areas that may require coverage, use of this method can be costly. Both anthraquinone and methyl anthranilate are sprayed on the vegetation. Effectiveness of these sprays in repelling geese can be variable, depending on growing conditions, rainfall, mow- ing, and availability of alternate feeding areas. In general, repellency based on conditioned aver- sion is longer lasting than repellency based on taste. Water (methyl anthranilate). Methyl anthranilate formulations are also available for appli- cation to pools of standing water on airports and at other locations to repel birds from drinking and bathing. This application is best for temporary pools of water after rainfall, where repellency of only a few days is needed. Frightening agent [Avitrol™ (4-aminopyridine)]. Avitrol is registered for repelling pigeons, house sparrows, blackbirds, grackles, cowbirds, starlings, crows, and gulls from feeding, nesting, loafing, and roosting sites. Birds eating Avitrol-treated baits react with distress symptoms and calls, behaviors that frighten away other birds in the flock. Avitrol, although registered as a “frightening agent,” is lethal. Therefore, recognize that Avitrol is a toxin to the birds that con- sume treated bait. Avitrol-treated bait is diluted with untreated bait so most birds in the flock do not eat treated bait. The primary use of Avitrol at airports has been in pigeon control around buildings. The use of Avitrol requires knowledge of: • The feeding patterns of the birds, • Proper prebaiting procedures to ensure bait acceptance and avoidance of nontarget species, and • Removal of dead birds after treatment. Trained Falcons and Dogs Trained falcons and other birds of prey have been used intermittently at various airports in Europe and North America to disperse birds since the late 1940s. The advantage of falconry is 60 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Methyl anthranilate can be applied to standing water at airports to repel gulls. (Photo courtesy USDA)

that the birds at the airport are exposed to a natural predator for which they have an innate fear. The disadvantage is that a falconry program is expensive, requiring several birds that must be kept and cared for by a crew of trained, motivated personnel. Also, the effectiveness of falconry programs in reducing strikes has been difficult to evaluate. The use of trained dogs, especially border collies, to chase geese and other birds from golf courses, airports, and other sites is a recent development. As with falcons, the advantage is expo- sure to a natural predator. The disadvantages are that the dog must be under the control of a trained person, and the dog must be cared for and exercised 365 days a year. A dog will also have little influence on birds that are flying over the airport. Radio-Controlled Model Aircraft Radio-controlled (RC) model aircraft, which provide both visual and auditory stimuli, occasionally have been used to harass birds at airports. One advantage is the RC aircraft is under the control of a person and can be directed precisely to herd the birds away from the airport runway. A second advantage is the RC aircraft can be used on an “as needed” basis with little maintenance required between flights. Some RC aircraft have been designed to appear like a falcon and even to remotely fire pyrotechnics. The disadvantage is that a trained person is required to operate the RC aircraft in an airport environment. Before using RC aircraft, ensure that the radio frequencies used are compatible with other radios used in the airfield environment. Nonlethal Projectiles Use paint balls and rubber or plastic projectiles, fired from paint-ball guns and 12-gauge shot- guns, respectively, to reinforce other dispersal techniques employed to repel Canada geese, roost- ing vultures, and perhaps other species of birds. Use a high-quality paintball gun to provide enough accuracy and velocity (typically fired 20 to 100 ft from bird). The proper distance for fir- ing varies by projectile and species of bird. The objective is to shoot from enough distance so that the projectile induces temporary pain, but no injury, in the bird struck. There are several types of rubber or plastic projectiles (slugs, buckshot, pellets, and beads) for use in a shotgun. Person- nel using these techniques need to be trained in firearm use and in the use of the particular pro- jectiles being used. Wildlife Control Strategies and Techniques at General Aviation Airports 61 Many airports are using trained dogs to chase away birds. Because of the cost, this may not be practical for small airports. (Photo E. Cleary)

Habitat Modification Habitat modification means changing the environment to make it less attractive or inaccessi- ble to the problem wildlife. All wildlife require food, cover, and water to survive. Any action that reduces, eliminates, or excludes one or more of these elements will result in a proportional reduc- tion in the wildlife population at the airport. Habitat modifications to make the airport and sur- rounding area as unattractive as possible to hazardous wildlife must be the foundation of every airport’s wildlife hazard management program. Initially, management actions to reduce food, cover, and water at an airport might be expen- sive. However, when costs are amortized over several years, these actions could be the least expensive approach to reducing wildlife populations at the airport. Once a habitat modification is done correctly, it is generally not necessary to go back and do it again. Also, these control meth- 62 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports As part of their training program, these students are learning how to safely use paintball guns to disperse problem wildlife. (Photo E. Cleary) Gulls and cattle egrets are attracted to mowing operations that flush insects and expose small rodents. Conduct mowing opera- tions at night to prevent this. (Photo E. Cleary)

ods are generally well accepted by the public and minimize the need to harass or use lethal means to remove wildlife on the airport. Food Be aware of food attractants for birds that exist at and in proximity to the airport. At the air- port, require bird-proof storage of food waste, ban bird feeding, and promote good sanitation and litter control programs. Some of the more common urban food sources for birds at and near airports include hand- outs from people in taxi stands and parks, grain elevators, feed mills, sewer treatment plants, and improperly stored food waste around grocery stores, restaurants, and catering services. Rural food sources attractive to birds include sanitary landfills, feedlots, certain agricultural crops (especially cereal grains and sunflower), and spilled grain along road and rail rights-of-way. Because most, if not all, agricultural crops can attract hazardous wildlife during some phase of production, the FAA recommends against the use of airport property for agricultural produc- tion, including hay crops. For nearby off-airport areas, work closely with local governmental entities and landowners to discourage land use practices and activities that provide food sources for problem bird species. If the airport has no financial alternative other than to produce income with agricultural crops to maintain the viability of the airport, then the airport should follow the crop distance guidelines listed in the table entitled “Minimum Distances between Certain Air- port Features and Any On-Airport Agricultural Crops” found in FAA AC 150/5300-13, Airport Design. Weigh the cost of wildlife control and potential accidents against the income produced by the on-airport crops when deciding whether to allow crops on airport grounds. Do not use trees and other landscaping plants that produce fruits or seeds attractive to birds for the street side of airports. On airside areas, the large expanses of grass and forbs can sometimes pro- vide ideal habitat for rodent and insect populations that attract raptors, gulls and other bird species, and mammalian predators such as coyotes. In addition, grasses allowed to produce seed heads can provide a desirable food source for doves, blackbirds, and other flocking species. Managing airside vegetation to minimize rodents, insects, and seeds might be complex, requiring insecticide, herbi- cide, and rodenticide applications; changes in vegetation cover; and adjustments in mowing sched- ules (for example, mowing at night to minimize birds feeding on insects exposed by the mowing). Such management plans will need to be developed with professional wildlife biologists and horti- culturists knowledgeable about the local wildlife populations, vegetation, and growing conditions. Water Water acts as a magnet for birds; therefore, eliminate standing water at the airport to the great- est extent possible. Fill or modify depressions in paved and vegetative areas as well as disturbed areas at construction sites that collect standing water after rain to allow rapid drainage. This is important at coastal airports where freshwater is attractive to birds for drinking and bathing. Do not build retention ponds, open drainage ditches, outdoor fountains, and other wetland sites at or near airports. The FAA recommends either a 5,000-ft separation (for airports that serve primarily piston-powered aircraft) or a 10,000-ft separation (for airports serving turbine-powered aircraft) between known attractants of hazardous wildlife and an airport’s AOA, loading ramps (apron areas), and aircraft parking areas. Refer to FAA AC 150/5200-33, Hazardous Wildlife Attractants on or near Airports, for a more detailed discussion of the recommended separation distances. Where possible, modify storm water detention ponds to allow a maximum 48-hour detention period for the design storm. Avoid or remove retention ponds and detention ponds featuring dead storage to eliminate standing water. Design detention basins to remain dry between rain- falls. Where constant flow of water is expected through the basin, or where any portion of the basin bottom might remain wet, design the detention facility to include a concrete or paved pad and/or ditch/swale in the bottom to prevent vegetation that might provide nesting habitat. Wildlife Control Strategies and Techniques at General Aviation Airports 63

When it is not possible to drain a large detention pond, use physical barriers, such as bird balls, wire grids, pillows, or netting, to deter birds and other hazardous wildlife. Evaluate the use of physical barriers and ensure that they will not adversely affect water rescue. Encourage off-airport storm water treatment facility operators to incorporate suitable wildlife hazard mitigation techniques into their operating practices when the facility is located within the separation criteria specified in FAA AC 150/5200-33. Shelter All wildlife require shelter for resting, roosting, escape, and reproduction. Nonmigratory Canada geese in urban areas, left undisturbed, will establish territories on corporate lawns, golf courses, and even building roofs associated with nearby ponds. Pigeons, house sparrows, and 64 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Fish-bearing water attracts birds because it provides both a food source and a water source. Here, a great egret and an anhinga hunt for fish next to the runway at a southern airport. (Photo E. Cleary) Even though this detention pond was originally designed to drain within 48 hours following the design storm, additional work is needed to ensure it drains completely. (Photo courtesy FAA)

European starlings use building ledges, abandoned buildings, open girders and bridgework, and dense vegetation for shelter. Blackbirds use marsh vegetation, such as cattails, for nest- ing and roosting. Solve many bird problems by removing such areas or by excluding birds from them. Take care when selecting and spacing plants for airport landscaping. Avoid plants that pro- duce fruits, nuts, berries, or seeds wanted by birds. Also avoid creating areas of dense shelter for roosting, especially by European starlings and blackbirds. Thinning the canopy of trees, or selec- tively removing trees to increase their spacing, can help eliminate bird roosts that form in trees at airports. Managing an airport’s airside ground cover to minimize bird activity is a controversial sub- ject in North America due to confusing and inconsistent guidelines and narrow research proto- cols. The general recommendation, based on studies in England and Canada in the 1960s and 1970s, has been to maintain a uniform stand of grass at a height of 6 to 10 in. (recommended by Transport Canada), 6 to 12 in. (by numerous European nations), or 7 to 14 in. (mandated by the U.S. Air Force). Grass height maintained in the range of 6 to 12 in. is recommended whenever conditions allow. Intermediate height grass, by interfering with visibility and ground move- ments, may discourage many species of flocking birds such as blackbirds, starlings, gulls, and others from loafing and feeding. However, the limited studies on single species preferences conducted in North America have not provided a consensus on the utility of tall-grass man- agement for all species. For example, though not preferred by most species, taller grass may not always discourage larger birds such as Canada geese, cattle egrets, and herons, and other methods may be needed to disperse these birds from airport property. In addition, grass must be mown before it reaches the upper threshold height to prevent increased rodent popula- tions, a food source for raptors. Finally, maintenance of uniform stands of intermediate height grass is difficult for some airports because of varying soil conditions and the need for fertilizer or herbicide applications. Arid regions in the western United States also cannot maintain grass without irrigation. Consult with professional wildlife hazard management biologists and horticulturists to develop a vegetation type and mowing schedule suitable for the growing conditions and wildlife at your airport location. The main principle to follow is to use a vegetation cover and mowing Wildlife Control Strategies and Techniques at General Aviation Airports 65 While Canada geese prefer to forage in shorter grass, they can sometimes be found in taller vegetation and require harassment efforts to disperse them. (Photo E. Cleary)

regime that does not result in a buildup of rodent numbers or the production of broad-leaved vegetation, seeds, forage, or insects desired by birds. Exclusion Techniques Architects should consult with biologists during the design phase of buildings, hangars, bridges, and other structures at airports to minimize exposed areas that birds can use for perch- ing and nesting. For example, tubular steel beams are much less attractive as perching sites for starlings and pigeons than are I-beams. If desirable perching sites are present in older structures, close off these sites (such as rafter and girded areas in hangars, warehouses, and under bridges) with netting. Hang curtains made of heavy-duty plastic sheeting, cut into 12-in. strips in ware- house or hangar doorways, to discourage birds from entering these openings. Install anti-perching devices, such as spikes, on ledges, roof peaks, rafters, signs, posts, and other roosting and perch- ing areas to stop certain birds from using them. Change the angle of building ledges to 45o or more to deter birds. Incorporate bird exclusion or deterrence into the design of structures to pro- vide the most effective, long-term solution. Reduce gull and waterfowl use of retention ponds and drainage ditches with overhead wire grid systems. Wires can be extruded metal, heavy gauge monofilament, or braided “superlines” used for fishing. Wires spaced 10 ft apart or in a 10- x 10-ft grid will discourage most gulls and waterfowl from landing. Similar wire systems have successfully kept gulls off of roofs and out of landfills, and crows out of electrical substations. When it is desirable to eliminate bird use, install netting over small ponds and similar areas. Be aware that birds may become tangled in the net- ting, and maintenance problems arise with high winds and freezing weather. Complete cover- age of ponds with plastic, 3-in. diameter “bird balls” or floating mats will exclude birds and yet allow evaporation of water. Designing ponds with steep slopes will discourage wading birds such as herons. Use culverts in drainage ditches whenever possible. 66 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Recommendations about airport infield grass height must be made on a prescription basis. Among other considerations, the prescription must take into account the species of birds causing problems, the general environment of the airport, and the local and regional climate. (Photo courtesy USDA)

Population Management Live Capture Chemical capture. Alpha chloralose (A-C) is registered with the FDA as an immobilizing agent for use in capturing waterfowl, coots, and pigeons. A-C can only be used by people cer- tified to use it or by people working under the authority of personnel with the USDA/WS. A-C, incorporated into bread baits, is ideal for selectively capturing ducks, geese, and coots that can be hand-fed at urban ponds and parks. Corn baits are recommended for pigeons or groups of waterfowl or coots that cannot be individually baited. Birds eating a clinical dose of A-C can be captured in 30 to 90 minutes. Complete recovery normally occurs within 8 hours but can take up to 24 hours. Live trapping. Trapping wild animals requires a high degree of knowledge and skill, and is generally most successful when undertaken by skilled professionals. The major advantage of live trapping is selectivity; any nontarget birds can be released unharmed. The major disadvantage is that live trapping is often labor intensive. Tend traps frequently and remove captured animals; in the case of cage traps with decoy birds, provide food and water. Hygnstrom et al. (1994) pro- vide detailed descriptions of various trap designs. Use trapping to remove raptors (hawks and owls) in the AOA. Trapping should be done by professionals having the skills and proper tools to remove the birds without injuring them. Because raptors are desirable parts of bird communities, most permits for trapping raptors require banding the birds and relocating them into suitable habitat at least 50 miles from the airport. Live trapping with walk-in traps on roofs or other isolated sites can be done to remove pigeons at airports. If relocated, pigeons can fly long distances to return to the site of capture. Therefore, euthanize captured pigeons following American Association of Wildlife Veterinarians (AAWV) guidelines. Net launchers use a blank rifle cartridge to propel a net. Fired from the shoulder much like a shotgun or rifle, net launchers can capture individual or small groups of problem birds that can be approached within about 50 ft. Wildlife Control Strategies and Techniques at General Aviation Airports 67 Because of the extremely high water table and frequent heavy rains in the area, it was necessary to install open canals to ensure proper drainage at this airport. The banks are cement lined and very steep to discourage wading birds. (Photo E. Cleary)

Lethal Control Some lethal control is usually necessary as part of a GA airport’s integrated program to con- trol problem wildlife. Use lethal control only as a last resort after all other reasonable nonlethal options (habitat modification, exclusion techniques, and repellent actions) have been exhausted, and there is an ongoing threat to public safety. Managing a wildlife hazard situation at an airport might require killing a particular animal or require that a local population of a problem species be reduced until a long-term, nonlethal solution is completed (for example, relocation of a nearby gull nesting colony). In addition, lethal control of a few individuals is sometimes neces- sary to reinforce nonlethal frightening techniques. Develop the following information to justify lethal control and to lessen adverse public reac- tion to a program involving killing: • Describe the situation and how the presence or behavior of the animal(s) is a threat to safe air- craft operations; • List the hazing or harassment strategies that were used and their results; 68 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Live trapping of raptors requires a high degree of skill. Remem- ber that all raptors are protected by federal law and may only be taken with a federal depredation permit. (Photo courtesy USDA) Occasionally shooting some birds at an airport will help reinforce nonlethal repellent techniques. (Photo courtesy USDA)

• Describe the method used (including who, when, and what); • Document that the killing procedures were correct (that is, followed AAWV guidelines) and specific for the target wildlife species; • Identify the location on the airfield where the action was taken; and • Document the effectiveness of the killing program in helping to solve the problem (for exam- ple, decrease in bird strikes). Recommend steps to be taken, if any are likely, to reduce the need for killing in the future. Remember: Obtain all necessary state and federal depredation permits. Active migratory bird nests (containing eggs or chicks) are protected by federal law and may not be taken without a federal depredation permit. For some species of migratory birds, nests that do not contain eggs or chicks may be removed without a federal depredation permit. Eagle nests may not be taken at any time without a federal permit. Each situation will have to be addressed on a case-by-case basis, depending on the species of bird, level of threat posed, location relative to runways, bird movement patterns, and other factors. Destroying nests and eggs. Do not allow Canada geese, mute swans, and gulls to nest on airport property. Provided the correct permits are in place, destroy (break eggs and remove nest material) any goose, mute swan, or gull nests with eggs found at an airport. Egg addling (oiling, shaking, or puncturing), whereby the birds continue to incubate nonviable eggs, is not recom- mended for airports, as it encourages the nesting birds (and any nonbreeding birds associated with them) to stay at the airport. At the time of nest destruction, harass the adult birds from the airport. Check the nesting area weekly for renesting until the end of the nesting season (gener- ally the end of June). As an alternative to harassment, it may be better to shoot nesting geese and mute swans. Mute swans and Canada geese are protected by federal and often state laws. Destroy nests of pigeons, starlings, and house sparrows whenever they are encountered in air- port buildings and structures. Where practical install physical barriers to prevent renesting (see the “Exclusion Techniques” subsection in the “Strategies and Techniques for Controlling Birds” section in Chapter 3). Shooting. Shooting birds in an airport environment generally falls into two main categories: quietly, or loudly as a reinforcement of audio and visual repelling techniques. First, pigeons using Wildlife Control Strategies and Techniques at General Aviation Airports 69 Adopt a zero tolerance policy for waterfowl and gull nesting on airport property. Destroy goose nests and eggs. Here a U.S. Fish and Wildlife employee is chasing a nesting pair of Canada geese from their nest, preparatory to removing the nest and eggs. (Photo courtesy L. Terry)

hangars, bridge girders, and other sites can be shot at night with an air rifle. This nighttime shoot- ing is done quietly and discretely, with the objective being to disturb the birds as little as possi- ble so that the maximum number can be removed. In the second category of shooting, common birds, such as gulls and geese, in the AOA that are not responding to various repellent methods can be shot with a 12-gauge shotgun. This shooting is done during daylight, in the open, so that other birds can witness the action. 70 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Remember: Shooters must make positive identification of all target birds before shooting. This will reduce the risk of killing nontarget birds. (Photo courtesy USDA) Remember the four cardinal rules when considering shooting problem birds. 1. Use only personnel who have an excellent knowledge of wildlife identification and are trained in the use of firearms. 2. Use the proper gun and ammunition for the situation. 3. Have necessary federal and state wildlife kill permits in place, and keep accurate records of killed birds by species and date. 4. Notify airport security, air traffic control, and, if appro- priate, the local law enforcement authority.

Shooting birds can have several effects on a flock: • It reinforces other audio or visual repelling techniques; • The loud noise, coupled with the death of one or more of the flock members, can frighten the rest of the flock away and • The target birds are permanently removed. Before starting a shooting program, local ordinances against the discharge of firearms within certain distances of buildings, or within the city limits, may need to be waived. Oral toxicants. Currently in the United States, only one oral toxicant, DRC-1339, or Starli- cide™ (active ingredient 3-chloro-p-toluidine hydrochloride), is registered with the U.S. EPA for use in bird population management. Starlicide (0.1% active ingredient) is formulated in a pellet bait for use at feedlots to control starlings and blackbirds. DRC-1339 (98% active ingredient) can be formulated with a variety of baits and used to control starlings, pigeons, gulls, ravens, and black- birds under certain conditions, some of which might be applicable at GA airports. The control of pigeons around airport buildings and starlings roosting at or near an airport are the situations most likely applicable. Only USDA/WS personnel or persons working under their direct super- vision can use DRC-1339. Wildlife Control Strategies and Techniques at General Aviation Airports 71 The use of toxic baits to kill target birds without affecting nontar- get species requires considerable skill and patience. (Photo E. Cleary)

The use of toxic baits to kill target birds without affecting nontarget species requires consid- erable skill and patience. Daily movement patterns of the target birds among feeding, loafing, and roosting sites must be determined so that attractive bait sites that are controlled from pub- lic access (such as a roof top) can be selected. The proper bait (a highly desired food) must be selected, and the birds then must be prebaited, often for a week or more, to ensure good bait acceptance and that nontarget animals are not visiting the bait site. Proper prebaiting is the most critical step of a successful program. During the baiting period, all uneaten bait must be removed daily. With DRC-1339, birds typically die one to three days after bait ingestion; therefore, areas surrounding bait sites will need to be searched for several days after baiting to remove dead birds. Contact toxicants. Hollow metal perches containing a wick treated with the toxicant fenthion were previously used to control pigeons, house sparrows, and starlings in and around buildings. However, the U.S. EPA has phased out the use of fenthion-treated perches because of concerns for secondary poisoning of raptors and mammalian scavengers feeding on dying birds. No replacement chemical has been registered at this time (2009). If toxic perches become available, their use outside of buildings is not recommended because there is no way of preventing nontarget birds from landing on them. Even when used inside buildings, careful placement of perches and monitoring must be done to ensure nontarget birds such as swallows are not exposed to the toxicant. All dead birds must be picked up and properly disposed of by appropriate personnel. Strategies and Techniques for Controlling Large Mammals Repelling Techniques Auditory Repellents One of the major wildlife problems identified by our survey questionnaires, on-site surveys, and analysis of data from the FAA’s National Wildlife Aircraft Strike Database, is that large mam- mals (for example, deer and cattle) and medium-sized mammals (such as coyotes and feral dogs) 72 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Never reject the simple just because it is simple. Simple meth- ods often work better than complicated methods. This man’s job is to patrol a particular area of an international airport and chase away hazardous wildlife by making noise. (Photo E. Cleary)

can pose a serious threat to aircraft safety at GA airports. Deer are the most hazardous species for both GA and air carrier aircraft. Probably the most commonly used auditory scaring device for deer is the propane cannon. However, deer rapidly habituate to propane cannons. Propane cannon use on airports to repel deer and other mammals from airport runways is not recom- mended except for short-term (a few days) emergencies until a more permanent solution (fenc- ing or deer removal) can be achieved. Other electronic noise-generating devices have also proven ineffective in repelling deer or other mammals for more than a few days. Pyrotechnics also pro- vide only short-term repellency for mammals. Visual Repellents Visual repellents such as flags and effigies have proven ineffective for repelling mammals. Their use is not recommended for keeping deer or other mammals away from airports. Red lasers are also ineffective in dispersing deer. Chemical Repellents There are several taste and odor repellents marketed to repel deer, rabbits, and other mam- mals from browsing on vegetation (Hygnstrom et al. 1994). Some are applied directly to the veg- etation; others are used as area (odor) repellents (for example, predator urine). Some of these products might be suitable for short-term protection of valuable landscaping plants and fruit trees. However, their use on airports to repel or discourage deer or other mammals is not rec- ommended because they are unlikely to have any influence on wildlife movements in the airport operating area. Trained Dogs The use of trained dogs, especially border collies, to chase deer from golf courses, airports, and other sites is a recent development. The advantage is that deer see the dog as a natural predator. The disadvantages are that the dog must be under the control of a trained person, and the dog must be cared for and exercised every day. Habitat Modification Food Take care when selecting and spacing plants for airport landscaping. Avoid plants that pro- duce fruits and seeds wanted by deer and other mammals. On airside areas, large expanses of low-growing dense vegetation can provide ideal habitat for rodent and insect populations that attract raptors, gulls, and mammalian predators such as coyotes. Managing airside vegetation to minimize rodents, insects, and seeds might be complex, requiring insecticide, herbicide, and rodenticide applications; changes in vegetation cover; and adjustments in mowing schedules. Such management plans will need to be developed with professional wildlife biologists and horticulturists knowledgeable about the local wildlife populations, vegetation, and growing conditions. Food waste from airport restaurants and local and/or transient pilots, if not properly disposed of, can attract problem mammals such as coyotes, raccoons, dogs, cats, rats, and mice. Ensure that all food waste is placed in closed containers, inaccessible to wildlife, until it is removed from the airport. Food provided by airport employees for feral dogs and cats can be a major attractant not only to the feral animals but to problem wildlife, such as coyotes, raccoons, and rats. In addition to posing a threat to aviation safety, the feral animals can pose a threat to the health of airport employees. Any feeding of feral dogs and cats by airport personnel should be stopped. Wildlife Control Strategies and Techniques at General Aviation Airports 73

Water Standing water can be highly attractive to all wildlife—mammals and birds—particularly in areas where fresh water is scarce. Where possible, modify storm water detention ponds to allow a maximum 48-hour detention period for the design storm. Avoid or remove retention ponds and detention ponds featuring dead storage to eliminate standing water. Design detention basins to remain dry between rainfalls. Where constant flow of water is expected through the basin, or where any portion of the basin bottom might remain wet, design the detention facility to include a concrete or paved pad and/or ditch/swale in the bottom to prevent vegetation that might pro- vide bird nesting habitat, which in turn could attract mammalian predators. Use rock-lined, steep-sided, narrow, linearly shaped basins to facilitate the control of hazardous wildlife. The rocks help hide the water during periods of low inundation. 74 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Improperly disposed of trash is attractive to many species of hazardous wildlife. Always ensure that all trash is handled correctly. (Photo E. Cleary) Standing water can be very attractive to birds. This is a construction site at a midwestern airport. (Photo courtesy FAA)

When it is not possible to drain a large detention pond, use physical barriers, such as bird balls, wire grids, pillows, or netting to deter birds and other hazardous wildlife. Evaluate the use of physical barriers and ensure that they will not adversely affect water rescue. Encourage off-airport storm water treatment facility operators to incorporate suitable wildlife hazard mitigation techniques into their operating practices when the facility is located within the separation criteria specified in FAA AC 150/5200-33. Shelter All wildlife require shelter for resting, escape, and reproduction. Dense stands of trees and undergrowth on airport property can provide excellent shelter for deer, coyotes, rodents, and other wildlife. In general, clear, or at least sufficiently thin, these habitats to eliminate the desired shelter and to allow easy visual and physical access by wildlife control personnel. Piles of construction debris and discarded equipment, unmowed fence rows, and other unmanaged areas are not only aesthetically unpleasing but typically provide excellent shelter for rats and mice as well as den sites for woodchucks, feral dogs, and coyotes. Eliminate such areas at airports. Exclusion Techniques Large- and medium-sized mammals can pose a serious threat to aircraft safety. At GA air- ports, institute a “zero tolerance” policy for deer, livestock, and other large mammals in the AOA because of their severe threat to aviation safety. The best, although most costly, procedure for excluding these animals from the air operations area is proper fencing. The FAA recommends a 10- to 12-ft chain-link fence with 3-strand barbed wire outriggers. Occasionally an airport may be able to use an 8-ft chain-link fence with 3-strand barbed outriggers, depending on the deer activity in the area. Use a 4-ft skirt of chain-link fence material, attached to the bottom of the fence and buried at a 45o angle on the outside of the fence, to prevent animals from digging under the fence and to reduce the chance of washouts. This fencing also increases airport security. There are many electric fence designs for excluding deer, as discussed in Hygnstrom et al. (1994) that are not as costly as permanent fencing, but have drawbacks in safety and maintenance. Wildlife Control Strategies and Techniques at General Aviation Airports 75 This photo shows an airport’s perimeter fence with a 4-ft skirt attached to prevent animals from digging under it and to reduce washouts. (Photo courtesy PDX)

Properly install and maintain all fencing. Keep the fence line right-of-way free of excess veg- etation. Patrol the fence line daily; fix any washouts, breaks, or other holes in the fence as soon as they are discovered. Take immediate action to remove any deer or other large mammals seen on or near the AOA. Use cattle guards to stop hoofed livestock (cattle and horses) from entering fenced areas through permanent openings kept for vehicular access. These devices, if at least 15 ft long and perpendicular to the fence, will also stop deer from entering through gated areas at airports. Population Management Live Capture Chemical capture. Large mammals, such as deer, can be captured with tranquilizer guns. However, the disposition of the captured animal can be problematic. Live capture and reloca- tion of deer is not recommended or allowed in most states because deer populations are at or near carrying capacity. When the use of firearms is not safe or practical, the use of tranquilizer guns might be appropriate. Capturing animals with tranquilizer guns requires personnel with a high degree of skill and experience in their use. When used in an airport environment, safeguards must be in place to ensure partially tranquilized deer do not enter runway areas. Live trapping. Specialized drop-door traps, drop nets, or rocket net setups can be used to live capture deer, but live capturing deer is not recommended for airport situations for reasons outlined above. Use basket or box-type live traps to capture medium-sized mammals such as raccoons, skunks, woodchucks, beavers, and feral dogs. Leg-hold traps and snares can be used to capture coyotes, feral dogs, and raccoons. Successful mammal trapping, especially with leg-hold traps and snares, requires a high degree of skill and experience. Once set, check traps frequently (at least once every 24 hours and more often in hot or cold weather). Trappers must be knowledgeable in procedures for handling and euthanizing mammals. State and local regulations may restrict the use of some types of traps. 76 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Initially, fencing such as that shown here is expensive. However, when the cost is amortized over several years, the long-term cost drops dramatically. Also, because this type of fencing greatly improves airport security, it may be possible to share the cost of this type of fencing with the FAA. (Photo courtesy USDA)

Lethal Control Shooting. Adopt a “zero tolerance” policy for deer at airports. If fencing is inadequate to keep deer away from an airport or if deer have gotten inside the airport’s fence, shooting is the best procedure for removing the deer. When practical, donate the meat from deer that are removed from airports to a local charity. Because of inherent safety considerations and to ensure safe and efficient removal, shooting at airports should be done by professional sharpshooters, using non-ricocheting bullets in rifles equipped with night vision scopes and noise suppressers. Elevated shooting stands can be erected on the ground or on a truck bed to direct shots toward the ground. Deer are protected in all states. Shooting of deer at airports must be coordinated with the state wildlife agency. GA airports may consider having local police units do the shooting. At GA airports with deer problems, encourage hunting during the regular deer season in areas adjacent to airports with deer problems to reduce the population in the general area. Archery hunting sometimes can be used in areas closed to firearms. Wildlife Control Strategies and Techniques at General Aviation Airports 77 All live traps should be tended at least daily. Dispose of trapped animals in accordance with state and local regulations. (Photo E. Cleary) Where safe and legal, deer hunting on and near airport grounds is a good way to reduce deer numbers in the area. (Photo E. Cleary)

Lethal traps. Depending on state and local laws, Conibear™ (body gripping) traps can be used to remove woodchucks, beaver, and other medium-sized mammals that create problems at air- ports. Neck snares can be used to capture coyotes, beaver, and certain other mammals. The use of these lethal traps requires a high degree of skill and experience to selectively capture the target ani- mal. Once set, traps must be checked frequently (at least once every 24 hours and more frequently in hot or cold weather) to euthanize any animals that might be captured but not killed. Trappers must be knowledgeable in procedures for handling and euthanizing captured mammals. Strategies and Techniques for Controlling Small Mammals Toxicants Populations of small rodents (such as voles, house and deer mice, and Norway rats) may erupt in grassy and brushy areas or around construction debris at airports, attracting raptors and creat- ing a hazard to aviation. In general, control rodent populations by habitat management (mowing, sanitation, and cleanup of brushy areas and/or piles of debris). However, there may be situations where the use of a rodenticide is appropriate to reduce rodent populations in airside vegetation. Note: The control of commensal rodents—rats and house mice—in airport terminal build- ings and other facilities will not be discussed here. These jobs are usually handled by private pest control operators. There are two types of rodenticides that may be available for use in airside vegetation: anti- coagulants and acute toxicants. Anticoagulants cause the rodent to die from internal bleeding. Some anticoagulants require multiple feedings to induce sufficient bleeding for death, whereas others require only a single feeding. Anticoagulant baits can be placed in various types of bait containers positioned in areas of high rodent activity. The only acute toxicant registered for aboveground treatment of field rodents is zinc phos- phide, available in pellet and grain bait formulations and as a concentrate for specialized bait for- mulations. Depending on registration label instructions, rodenticide baits can be broadcast in the vegetation or hand placed in burrows and runways. Care must be taken to minimize nontarget 78 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Before using any pesticide, always read and follow all label directions. (Photo E. Cleary)

bird and mammal exposure with broadcast and hand-placed baits. Anticoagulant baits can also be placed in various types of bait containers positioned in areas of high rodent activity. Fumigants At airports, burrowing rodents such as woodchucks (groundhogs) and prairie dogs can be killed by fumigation of burrows with either gas cartridges or aluminum phosphide tablets. Gas cartridges, ignited from a burning fuse after placement in the burrow, generate carbon monox- ide. Aluminum phosphide pellets react with moisture in the burrow to produce phosphine gas. Care must be taken to plug all burrow entrances with sod after placement of the cartridge or pel- lets in the burrow. Gas cartridges are a general use, over-the-counter pesticide. Aluminum phos- phide pellets can only be applied by certified pesticide applicators and might not be available in all states. As with all pesticides, it is critical to make sure the wildlife species you are treating is covered under the registration for your state. Notices to Airmen of Potential Wildlife Hazards Airport managers must maintain a safe aircraft operating environment. This may include restricting aircraft operations when immediate wildlife hazards exist at or near the airport. Air- craft movements at GA airports may not be subject to the same restrictive time schedule pres- sures as air carrier aircraft movements at Part 139 certificated airports. Recreational GA aircraft pilots do not have a rigid schedule to keep and may be able to delay their takeoff or landing to accommodate wildlife control problems at the airport. Because airport managers must maintain a safe aircraft operating environment, they can restrict aircraft operations when hazardous con- ditions such as wildlife on or near the runway require it. Admittedly, the pilot has the final deci- sion whether or not to land or takeoff. Private pilots may be able to delay their takeoff or landing with little or no consequences. Air couriers (bank, medical, and film), air taxies, or charter operations may be able to change or delay their operation schedules to allow airport personnel time to address imminent or recur- rent hazardous wildlife problems. Wildlife Control Strategies and Techniques at General Aviation Airports 79 Where legal, gas cartridges can be used to control burrowing rodents such as woodchucks and prairie dogs. (Photo E. Cleary)

Also, inherent in the idea of flight schedule modification is the idea of closing various run- ways, or the entire airport, if necessary, to address imminent or recurrent wildlife hazards. For example, pilots may be able to delay departure during a 20-minute period at sunrise or sunset during winter when large flocks of blackbirds cross an airport going to and from an off-airport roosting site. Also, air traffic controllers on occasion may temporarily need to close a runway with unusually high bird activity or a large mammal (for example, deer) incursion until wildlife control personnel can disperse the animals. Conclusions Habitat modifications to minimize food, water, and shelter, and physical or psychological barri- ers to exclude wildlife are the foundations of wildlife hazard management programs for airports. In addition, an integrated array of repelling techniques is necessary to disrupt normal behavior and to stress hazardous wildlife that attempt to use the airport environment. These repelling techniques must be used judiciously and be backed by real threats to minimize habituation. To this end, lethal 80 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports This Cessna aircraft, with only 80 hours of flight time, struck a large bird over a lake several miles from a midwestern airport. (Photo M. Mullen) Airfield approach lights provide ideal perches for hunting raptors. (Photo E. Cleary)

Wildlife Control Strategies and Techniques at General Aviation Airports 81 Laser Avian dissuader hand-held pistol style $1,095 each Desman laser rifle style $7,700 each Pyrotechnics Screachmer siren $45/100 rounds Bird banger $45/100 rounds Screachmer banger rocket $95/100 rounds Pyrotechnic Launchers Single shot launcher $34 each Double shot launcher $42 each Seven shot launcher $120 each Propane Cannon $290–$385 each Chemical Repellent Rejex-it® Migrate® for turf $90/gallon Visual Repellents Scarey Man®: multi-use unit $1,100 each Pre-set timer unit for Scarey Man $1,200 each Evil eye balloons $9.50 each Reflective tape 0.5" x 250' $2.50/roll 1.25" x 250' $7.50/roll Electronic Repellents Bird Gard® Super Pro $660 each Bird Gard Pro $220 each Mobile Bird Gard $690 each Table 3.1. Prices of some of the more commonly used bird control devices from one of the major suppliers in the United States, as of January 1, 2010. control of selected individuals of common species is sometimes necessary to reinforce repellent actions. Furthermore, the management of a wildlife hazard situation at an airport may require removal of a particular animal or group of animals or require that a local population of a problem species be reduced by lethal means until a long-term, nonlethal solution is implemented. Finally, the most critical factor for the success of a wildlife hazard management program is to have motivated and trained professionals who are knowledgeable about the wildlife species attempting to use the airport environment and the techniques used to manage the problems these species create. The ultimate responsibility for control of hazardous wildlife rests with the airport operator. The pilot-in-command is the final decision maker of whether or not to takeoff or land. Table 3.1 shows the current prices of some of the more commonly used bird control devices from one of the major suppliers in the United States, as of January 1, 2010. Tables 3.2 and 3.3 present a summary of the effectiveness and relative cost ($ through $$$$) of various control tech- niques for different wildlife species. The more $ signs, in general the more expensive the method. Trying to set an accurate price on many of the control methods mentioned is very difficult. Elim- inating a food source may be as easy as properly storing and disposing of garbage, or it may be as expensive as eliminating all farming at the airport. Eliminating water at the airport may only require opening some clogged drains or eliminating some small berms caused by snow removal, or it may require a completely new drainage plan for the entire airport. Appendix D presents a list of the minimum recommended equipment and current prices (January 1, 2010) that would be found at a small- to medium-sized airport.

Control Method for Birds C r o w s / J a y s / M a g p i e s B l a c k b i r d s S t a r l i n g s / M i n a s C o r m o r a n t s / A n h i n g a s D u c k s G e e s e S w a n s G u l l s H e r o n s E g r e t s C r a n e s P i g e o n s / D o v e s V u l t u r e s H a w k s F a l c o n s E a g l e s O s p r e y / K i t e s O w l s G a l l i n a c e o u s B i r d s S h o r e b i r d s T h r u s h e s S p a r r o w s Repelling Techniques Chemical repellents for birds F/$$ F/$$ F/$$ F/$$ F/$$ Audio repellents for birds Electronic sounds F/$$$ G/$$$ G/$$$ P/$$$ P/$$$ P/$$$ P/$$$ G/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ P/$$$ F/$$$ P/$$$ P/$$$ Pyrotechnics G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ Ultrasonic N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ N/$$ Visual repellents for birds P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ P/$$ Trained falcons and dogs to repel birds G/$$$$ G/$$$$ G/$$$$ G/$$$$ G/$$$$ G/$$$$ G/$$$$ G/$$$$ G/$$$$ Radio-controlled model aircraft to repel birds F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ F/$$$ Nonlethal projectiles to repel birds G/$$ G/$$ G/$$ G/$$ Table 3.2. Relative effectiveness and cost of control methods for hazardous birds. Effectiveness: B  best; G  good; F  fair; P  poor; N  not recommended. The more $ signs, the more expensive the method.

Habitat Modification Food B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ Water B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ Shelter B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ B/$$ Exclusion of Birds G/$$ G/$$ G/$$ G/$$ G/$$ F/$$ F/$$ F/$$ F/$$ G/$$ G/$$ F/$$ G/$$ G/$$ Population Management Capturing birds Chemical capture of birds F/$$ F/$$ F/$$ F/$$ F/$$ Live-trapping birds G/$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$$ G/$ Destroying eggs and nests G/$ G/$ G/$ G/$ G/$ G/$ Lethal control of birds Shooting birds G/$$$ F/$$$ F/$$$ G/$$$ G/$$$ G/$$$ G/$$$ F/$$$ G/$$$ G/$$$ F/$$$ G/$$$ F/$$$ F/$$$ P/$$$ N G/$$$ F/$$$ G/$$$ F/$$$ PG/$$$ P/$$$ Oral toxicants for birds F/$$ G/$$ Contact toxicants for birds N N N N N N N N N N N N N N N N N N N N N N Notification of Pilots of Wildlife Hazards G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$ G/$

84 Guidebook for Addressing Aircraft/Wildlife Hazards at General Aviation Airports Control Method for Mammals Canines Deer Cattle Raccoons Repelling Techniques Chemical repellents for mammals N N N N Audio repellents for mammals P/$$ P/$$ P/$$ P/$$ Visual repellents for mammals P/$ P/$ P/$ P/$ Habitat Modification Food B/$$ B/$$ B/$$ B/$$ Water B/$$ B/$$ B/$$ B/$$ Shelter B/$$ B/$$ B/$$ B/$$ Exclusion Techniques Exclusion of mammals G/$$$ B/$$$ B/$$$ F/$$$ Population Management Techniques Capturing mammals Chemical capture of mammals F/$$$ F/$$$ F/$$$ Live-trapping mammals G/$$ P/$$$$ B/$ Lethal control of mammals Shooting mammals G/$$ G/$$ N G/$$ Toxicants for small mammals Fumigants for small mammals Lethal traps for mammals G/$$ N N G/$$ Notices to Airmen of Potential Wildlife Hazards G/$ G/$ G/$ G/$ Table 3.3. Relative effectiveness and cost of control methods for hazardous mammals. Effectiveness: B  best; G  good; F  fair; P  poor; N  not recommended. The more $ signs, the more expensive the method.