Airport Wildlife Population Management (2013)

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8 Wildlife PoPulation ManageMent: an overvieW Wildlife is a public resource. Until the 1970s, wildlife man- agement was primarily a form of game management that focused on the husbandry and regulation of bird and mam- mal populations for sport and was synonymous with ani- mals that were hunted. In 1973, the U.S. Congress defined wildlife as the following: “the term fish or wildlife means any member of the animal kingdom, including without lim- itation any mammal, fish, bird (including any migratory, nonmigratory, or endangered bird for which protection is afforded by treaty or international agreement), amphib- ian, reptile, mollusk, crustacean, arthropod, or other inver- tebrate, and includes any part, product, egg, or offspring thereof, or dead body parts or parts thereof.” The Wildlife Society defines wildlife as “free-living animals of major sig- nificance to man.” Currently, most free-living animals are significant to humans, resulting in an expansion of its mean- ing, but often remain historically restricted to terrestrial and aquatic vertebrates. Wildlife management implies stewardship. As previously noted, airport sponsors, managers, and operators are legally obligated to manage wildlife to improve safety. For example, efforts to improve aircraft safety through wildlife manage- ment can be approached with the same degree of concern as with foreign object damage; both can have catastrophic con- sequences. Simplistically, wildlife management can be active, where measures are implemented to change existing situa- tions, or inactive, often described as passive or nonmanagement where no action is taken. Nevertheless, the goal of wildlife management has one of four options (Caughley 1994): 1. Make a population increase. 2. Make a population decrease. 3. Harvest a population for a continued yield. 4. Do nothing except monitor the population. All options are possible in airport wildlife population man- agement, dependent on the goals expected. In developing a wildlife population management strategy, three decisions are needed (Sinclair et al. 2006): 1. What is the desired goal? 2. Which management option is therefore appropriate? 3. By what action is the management option best achieved? Once the goals are established, airport managers can then determine the appropriate wildlife population management action (Decker et al. 2002). The establishment of the goals is a value judgment; however, how the goals are achieved involves technical evaluation, decisions, and application. Ecologically, a population can be defined as a group of organisms of the same species that occupies a given area over a specified time period. Species of a given population select habitats to occupy that meet their needs for food, water, and cover, often combined and referred to as habitat and depicted as a “habitat triangle” in ecological literature (see Figure 8). Food and water are necessary in acceptable amounts for a population to remain within a given space at a given time. Cover is shelter for wildlife and consists of vegetation and topographic features that provide places to feed, hide, sleep, play, and raise young (Leopold 1933). Wildlife uses cover for various reasons such as seasonal, refuge, resting, nest- ing, roosting, thermal, escape, bedding, and other types that are important in the varied life histories of different species (Krausman 2002). Thus, habitat refers to the resources and conditions present in an area that produce occupancy by a given individual and population to sustain survival and reproduction. Organisms live within a range of resource tolerances, or ecological amplitude, for each of the physical and biologi- cal components of their environment. Whenever the upper or lower optimal limit of the range is exceeded, organisms experience difficulties and may not survive at a particular location. Therefore, plants and animals survive only so long as they can compete successfully for resources. In general, each species is the product of a long evolutionary history that is governed largely by competition (Krausman 2002; Bolen and Robinson 2003; Sinclair et al. 2006). This evolutionary history results in a species’ steady improvement in the way they “fit” into their environment. For some species, the fit is tight, with no room for dealing with change. Such species are referred to as “specialists.” Most federal- or state-listed threatened and endangered species and those tied to specific habitat types are specialists, with some posing direct or indi- rect hazards to aviation. Examples include Whooping Cranes, Upland Sandpipers, Grasshopper Sparrows, and Burrowing Owls. In contrast, other species are highly adaptable and can deal with a wide range of environmental conditions; these are called “generalists.” Generalists include such species as chapter two airPort Wildlife PoPulation ManageMent

9 gulls, pigeons, corvids, starlings, coyotes, deer, commensal rodents, and others that are often the most significant hazard- ous species on airports. In both cases, the species possess a unique ability to live within its own zone of tolerance and perform a unique role within the habitat. This role or function is known as its ecological niche. By understanding an organ- ism’s niche, airport operators can select the most appropriate wildlife management approach. Unfortunately, this variable nature of niche for each species results in no “cookie-cutter,” “silver bullet,” or “one size fits all” approach to effective wildlife management. Wildlife PoPulation ManageMent: airPort Wildlife Control For airports, wildlife control involves three general strategies (see Figure 9). The first two strategies deal with the direct manipulation of animal numbers; the third adjusts for future action based on the analysis of past control method effective- ness. These include: 1. A management action designed to restore an errant system to its previous stable state by reducing animal numbers. 2. Moving a system away from its stable state to another that is more desirable. In such cases, animal density is reduced and the new density enforced by continuous control operations. 3. The third wildlife population control strategy deals with adaptive management to evaluate effectiveness and continually adjust wildlife control methods. To achieve airport wildlife population control strategy objectives, specific methods can be divided into those aimed at: 1. Directly increasing mortality. 2. Directly reducing reproduction. 3. Indirectly manipulating mortality, reproduction, or both. Thus, integrated airport wildlife management consists of both direct action (the focus of this synthesis) and indirect action (habitat modification, harassment, deterrence, exclu- sion) of wildlife population control on airports. It is impor- tant to note that the success of an airport wildlife population control operation is not gauged merely by the reduction in population numbers or density of the targeted animals but rather by the reduction in the potential wildlife hazards to aviation operations and safety. In all cases, the prime respon- sibility of the airport operators and wildlife managers is to determine whether the wildlife population control measure adequately produces the desired effects. Such risk analysis is an essential part of continuous monitoring, record keep- ing, and adaptive management efforts to determine effec- tiveness of the wildlife management program consistent with Safety Management System principles. There are three circumstances where wildlife control mea- sures may not be an appropriate management action (Sinclair et al. 2006): 1. Where the costs exceed the benefits. 2. When the “targeted animal” is not the cause of the problem. 3. Where the control has an unacceptable effect on non- target animals. As previously discussed, habitat dictates wildlife occu- pancy; therefore, effective wildlife control follows the identification of habitat diversity on and near the airport. In general, increased habitat diversity results in a greater num- ber of species occupying a given area at a given time. If an airport has high habitat diversity (grasslands, woodlands, aquatic features, etc.), then there is a resulting increase in the available ecological niches that the airport habitats can sup- port. In most cases, wildlife will fill those available niches at population levels that the habitat resources can support, often referred to as carrying capacity. In contrast, if an airport has low habitat diversity and is fairly homogeneous, then there is a resulting decrease in ecological niche diversity. Because the niche diversity is fairly similar in homogeneous habitat, most likely fewer species will occupy this habitat and the FIGURE 8 Habitat triangle (Source: BASH Inc.). FIGURE 9 Cattle Egrets foraging near airport taxiway at MCO (Source: MCO).

10 because different species often require different man- agement techniques. 3. Why is the wildlife on the airport? Are they attracted to the airport for food, water, or shelter, or are they just flying over the airport from nighttime roosting sites to daytime feeding sites? The answer to this question will determine, to a large extent, the most appropriate control methods to use. 4. What are the daily and seasonal movement patterns of the wildlife among feeding, loafing, and roosting/ nesting areas? It is important to identify the times of day and seasons of the year, as well as locations on the airport where the wildlife pose the most critical threat to aviation safety and where they are most vulnerable to management actions. 5. What is the legal status at the federal, state, and local levels of the problem species? All wildlife species are not afforded equal legal protection by all levels of government. 6. What effective and legal management methods are available? In wildlife hazard management effective and legal are not necessarily synonymous. 7. How selective are these control methods? The objec- tive is to control only the target wildlife, not every species in the area. 8. How much will it cost to apply the selected control meth- ods? The cost of control might dictate which methods are practical, given the seriousness of the threat caused by the species. 9. What are public attitudes toward the problem wildlife species and the hazards that these species pose? area may have a lower overall carrying capacity and resul- tant risk to aviation operations. In general, given airports of similar size, a more homogeneous habitat will have fewer overall species but potentially a greater number of individu- als of these species occupying the given area at a given time. A more diverse habitat may have a greater number of spe- cies but with fewer numbers of individuals of certain species. Because habitat and ecological niche diversity determines what species occupy a given area at a given time, it is equally important to understand what species are present and in what numbers they are present on an airport. Unfortunately, wild- life may utilize the airport habitat differentially; occupants may be resident or transient. This is particularly true with birds that have both migratory and nonmigratory popula- tions. Wildlife activity can also vary on a daily and seasonal basis consistent with its life history characteristics. It can be seen that evaluating potential wildlife problems on and near airports can be extremely variable and poten- tially confusing. The following checklist provides guid- ance in solving any airport wildlife population problem by answering the following nine questions for each problem species (Cleary and Dolbeer 2005): 1. What is the wildlife doing that make the control of their numbers or damage necessary? The type of activity that needs to be controlled will determine both the severity of the problem and the type of control methods used. 2. Which species of wildlife are causing the problem? Accurate identification of the exact species is critical “Vegetation Rehabilitation and Direct Wildlife Control” Charlotte Douglas International Airport (CTL) Our airport performed a runway rehabilitation project where the runway safety areas were seeded with grass seed to prevent erosion. Unfortunately, these conditions attracted various species, most notably Mourning Doves and Rock Pigeons, leading to signifi- cant increases in bird strikes. Thus, we started aggressive direct wildlife control measures to reduce these populations leading to immediate drastic reductions in bird strikes by these species. Runway construction and Rock Pigeons feeding on newly seeded grass at CTL (Source: BASH Inc.).

11 The need for information about an airport’s habitat and associated wildlife before beginning any wildlife control activity is best accomplished by completing a Wildlife Haz- ard Assessment (WHA) and a subsequent Wildlife Hazard Management Plan (WHMP). These tools are discussed in detail later. In general, these efforts provide the scientific, biologic, and ecologic evidence of the habitat and its wildlife occupants necessary for the airport operator to answer the “who, what, why, where, and when” questions necessary in developing an effective integrated wildlife population man- agement strategy. Wildlife Hazard assessMents and Wildlife Hazard ManageMent Plans Because wildlife poses a significant threat to aviation, airport operators must be prepared to take immediate action to alle- viate unexpected incursions of hazardous wildlife into the airport operations area, loading ramps, or parking areas [14 CFR 139.337(a)]. Preparation for this is best accomplished by conducting an airport WHA followed by an FAA-approved WHMP, if necessary. FAA guidelines sometimes evolve over time as new infor- mation becomes available; therefore, airports are advised to consult the most current publications regarding the con- duct and content of WHAs and WHMPs. Currently, 14 CFR 139.337(b) requires that, in a manner authorized by the FAA administrator, each certificate holder must ensure that a WHA is conducted when any of the following events occurs on or near the airport: 1. An air carrier aircraft experiences multiple wildlife strikes; 2. An air carrier aircraft experiences substantial damage from striking wildlife; 3. An air carrier aircraft experiences an engine ingestion of wildlife; or 4. Wildlife of a size, or in numbers, capable of causing an event described in paragraph (b) (1), (2), or (3) of this section, is observed to have access to any airport flight pattern or aircraft movement area. The WHA is conducted by a qualified airport wildlife biologist as per FAA AC 150/5200-36A, who provides the scientific basis for the development, implementation, and refinement of a WHMP. General areas to assess are detailed in FAA AC 150/5200-33B. Although considered separate documents, parts of the WHA may be incorporated directly into the WHMP. Conducting a WHA, 14 CFR Part 139.337 (c)(2) requires the “identification of the wildlife species observed and their numbers, locations, local movements, and daily and seasonal occurrences.” During the WHA, qualified airport wildlife biologists use standardized data collection procedures to provide an objective assessment of hazardous wildlife in the airport environment that can be repeated in future years for comparative purposes in evaluating wildlife control measure effectiveness. Once the WHA is complete, it is submitted to the FAA for evaluation and determination of whether a WHMP needs to be developed for the airport. If the FAA determines that a WHMP is needed, the airport operator then formulates and implements a WHMP, using the WHA as the basis for the plan [14 CFR 139.337 (e)(1–3)]. In most cases, a WHMP is necessary and becomes a part of the airport’s certification manual that is annually reviewed by the FAA certification inspectors for compliance and implementation. dePredation PerMitting requireMents and ProCedures Before using any wildlife population control measure (e.g., taking migratory birds, dispersing roosts, manipulating nests or eggs, live-trapping, lethal trapping, applying toxicants, and shooting with live ammunition) as part of an airport wildlife management program, airports must first secure a Migratory Bird Depredation Permit from the U.S. Fish and Wildlife Service (USFWS) to comply with federal law. Air- ports could be advised that state laws are not always consis- tent with and may be more restrictive than federal law. In all cases, airports must also comply with the individual state’s requirements for specific state-regulated species in order to obtain a depredation permit and license from their respective state wildlife management agency, in addition to securing a federal Migratory Bird Depredation Permit. The first step in obtaining the necessary permits is to contact: 1. The nearest USFWS office. 2. The U.S. Department of Agriculture (USDA)/Wildlife Service (WS) state office. 3. State and local wildlife regulatory and licensing agencies. Contact information for these agencies is provided by state in Appendix A. An example of a depredation permit and accompanying instructions is provided in Appendix B. In addition to depredation permits, standing depredation orders are enforced by federal law to allow people to protect themselves and their property from damage caused by migra- tory birds. Provided no effort is made to kill or capture the birds, a depredation permit is not required to merely scare or herd depredating migratory birds other than threatened and endangered species or Bald or Golden Eagles (50 CFR 21.41). It is paramount that airport personnel properly identify the species involved and that permit conditions and reporting requirements are fully understood. Requirements may vary

12 4. U.S. Army Corps of Engineers (COE). 5. U.S. Environmental Protection Agency (EPA). 6. Various state agencies. federal and state laWs and regulations Wildlife population management is protected by overlapping federal, state, and local laws, regulations, and ordinances and enforced by a diversity of governmental regulatory agen- cies. The following is a listing of the more significant federal regulations and departmental policies that influence wildlife population management on or near airports. Synopses of these federal regulations are detailed in Cleary and Dolbeer (2005). 1. Title 14, Code of Federal Regulations, Part 139 (14 CFR 139). 2. Title 40, Code of Federal Regulations, Part 258.10 (40 CFR 258.10). 3. Title 50, Code of Federal Regulations, Parts 1 to 199 (50 CFR 1-199). 4. Migratory Bird Treaty Act (MBTA) of 1918. 5. Federal Endangered Species Act (ESA) (16 U.S.C. 1531 et seq.) of 1973. 6. Animal Damage Control Act (ADCA) of 1931. 7. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1947. 8. FAA Advisory Circulars (AC). 9. FAA Airports: Airports Certification Program Poli- cies and Guidance. 10. FAA Airports: Office of Airports Safety and Stan- dards Certalerts. significantly, especially at the state and local level. In addi- tion, certain species of migratory birds may be killed or cap- tured without a federal permit under specific circumstances, most of which relate to agricultural situations. Currently, a standing depredation order for airports regarding black- birds and related species states that “A federal permit shall not be required to control yellow-headed, red-winged, rusty and Brewer’s blackbirds, cowbirds, all grackles, crows, and magpies, when found committing or about to commit dep- redation 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).” Aviation safety on airports constitutes such a hazard. federal and state agenCies WitH Wildlife ManageMent resPonsibilities Oversight of wildlife population management is regulated and implemented by various federal, state, and local govern- ment agencies. Overlapping federal, state, and local regula- tions enforced by various government organizations protect wildlife and associated wildlife habitat. The following is a listing of the various federal and state agencies and organi- zations that oversee wildlife population management on or near airports. Agency roles and responsibilities are detailed in Cleary and Dolbeer (2005). 1. U.S.DOT, FAA. 2. U.S. Department of Interior (DOI), USFWS. 3. USDA/WS.