Top 12 Hazardous Species to Aircraft

White-Tailed Deer

White-tailed deer are a widespread species with populations throughout North America as well as South America and some Caribbean Islands. They are not found along the Southwestern Coast of the U.S. or the coast of British Columbia. Deer populations have increased greatly and they are found in a wide variety of habitats including urban areas. However, their preferred habitat is swamps and other riparian areas.

White-tailed deer are distinguished from other deer species by the white buttocks and underside of their tail, which is frequently flipped over their back. They are primarily browsers, feeding on the leaves, stems, and twigs of woody vegetation. They also frequently feed on mast, fruits, cultivated crops, and grasses.

Deer are responsible for approximately 67% of mammal strikes with aircraft. They have been responsible for 97% of aircraft collisions with mammals that have resulted in damage to the aircraft. Their large body size makes them extremely hazardous during an aircrafts takeoff runs and landing rolls.

A zero tolerance policy should be adopted for deer within the AOA, and all possible steps must be taken to keep deer off of the airfield. The most important measure for keeping deer off of the airfield is adequate fencing. A 10-12 foot fence with a three-strand barbed wire outrigger, as well as an apron buried at a 45 degree angle under the ground is recommended. This type of fence may be cost prohibitive, however, 5-9 strand electric fences may also be effective.

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Vultures

Vultures are scavengers that are most commonly seen soaring overhead while searching for food. Turkey vultures and black vultures are two common species in North America. Turkey vultures can be identified by their white flight feathers and featherless head that is red in adults and gray in juvenile birds. In flight they hold their wings in a slight v-shaped posture and frequently rock back and forth on the wind. Black vultures have gray featherless heads and white wing tips. They are primarily solitary birds, however, they will often congregate around other birds they observe near potential food or favorable wind conditions. Turkey vultures forage throughout the day using their powerful eyesight and a highly developed sense of smell.

Vultures may be attracted to areas on and around an airport for several reasons. A food source may be present in the form of an animal carcass or food waste. They may also be attracted to land formations like hills that provide wind updrafts. The abundance of paved areas on an airport also creates rising columns of warmer air. These features help them to save energy by allowing them to soar easily without having to flap their wings.

Airports can help to reduce the presence of turkey vultures by collecting any road-killed animals on airport grounds, as well as any other carcasses found in the AOA. Vultures may also be dispersed with various pyrotechnics while they are perched or flying at lower altitudes. Airport operators should also take steps to remove perching, loafing, and roosting areas.

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Canada Geese

Canada geese are distinguished from other goose species by their white cheek patch that contrasts with a black head, bill, and neck. Canada geese are also well known for their distinctive honking call, and v-shaped flight formations during migrations.

These birds are found in every U.S. State and are able to utilize a wide variety of habitats. They can be found almost anywhere with an open field of view and a readily accessible water body. These locations include urban areas, arctic tundra, and even the borders of deserts. Geese congregating in urban areas can often create many conflicts with the public. Accumulation of feces can contaminate water sources and degrade the quality of public parks. Geese feeding in a park can also increase bank erosion.

Canada geese are often considered the most potentially harmful wildlife species to aircraft. This is caused by their large body size and tendency to form large flocks. They are also frequently attracted to airports because of the large open areas of short grass and potential areas of standing water.

There are many management strategies available for attempting to reduce the danger caused by the presence of Canada geese. Managing the grass at a longer length at an airport combined with active harrassment is one of best ways to keep geese off of an airfield.

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Cranes

There are two North American crane species: the whooping crane and sandhill crane. Cranes are very large birds; the whooping crane is the tallest bird in North America with a height of 5 ft. These birds have long, slender legs and necks with mostly white bodies. Cranes are omnivorous, feeding on grains, seeds, invertebrates, and small vertebrates. They breed in marshes, bogs, and wet fields/meadows and lay their eggs on mounds of vegetation. Cranes feed by probing the ground with their long bills in grain fields, wetlands, and wet meadows.
Aircraft collisions with cranes can be extremely hazardous. Their large body size and tendency to form flocks during migration can cause severe damage during a strike. Cranes affinity for wet fields may bring them into grassy areas of airports to feed, particularly after precipitation events. Eliminating large seed/grain producing plants from airports will help reduce the chance of attracting these birds. Reducing populations of insects and small mammals can also decrease the attractiveness of an airfields turf. Harassing cranes off of an airport is also recommended to reduce the danger to aircraft. However, extreme caution should be used in these situations. Whooping cranes are a highly endangered species along with the Mississippi population of the sandhill crane.

Osprey

This is one of the largest birds of prey in North America. It is also found on every continent except Antarctica, making it one of the most widespread birds on the planet. Osprey are most readily identified by their white heads with a thick dark eyestripe. Osprey feed almost exclusively on fish that they catch with an aerial dive. Osprey nest in trees but will also utilize manmade structures as nesting platforms.

The large body size of osprey creates the potential for severe damage to aircraft during a birdstrike. Osprey may be attracted to an airport because of nesting or foraging sites nearby. Removing nesting sites and/or nests is often used as a way to reduce osprey presence at an airport. Eliminating or limiting access to open water will also reduce the danger of an aircraft collision with osprey.

Cormorants/Pelicans

Both cormorants and pelicans belong to the same order (Pelicaniformes) and have many similar traits and management issues. Double-crested cormorants are the most common and widespread of the six cormorant species in North America. They are the only cormorant that is commonly found inland far from the coast. They can be identified by their dark plumage, long bodies/necks, and slightly hooked beak. American white pelicans and brown pelicans are the two pelican species in North America. American white pelicans are more common and found in several regions and are identified by their large white bodies and large bill with extensible pouch.

Double-crested cormorants and brown pelicans feed on fish by diving below the waters surface. American white pelicans dip their large beaks to scoop up fish. These species nest on the ground or in trees, often in large colonies. Concentrations of birds in these colonies can create several conflicts with the public. Accumulation of fecal matter below nesting sites can kill trees and other vegetation, damaging the habitat of other wildlife species. Large numbers of these birds feeding in one area can also deplete fisheries and damage fish farms.

Cormorants and pelicans in the vicinity of an airport can pose a significant threat to aviation. They are large bodied birds that have the potential to cause severe damage during a collision. Cormorants and pelicans also frequently move in flocks which increases this potential hazard. They may be attracted to an airport by open water. Bodies of water in the vicinity of an airport may also provide feeding/nesting sites where these birds will congregate.

Population control efforts of cormorants and pelicans often include egg-oiling, nest destruction, and hazing at nest sites. Habitat modification of nesting areas to reduce nest site locations can also reduce the presence of these species. Lethal control of limited numbers of birds can also be used in extreme situations. At airports, the elimination of open water and hazing/lethal control of problem birds are the most effective methods of managing these species.

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Ducks

There are many species of ducks in North America with populations on the coasts as well as inland. Ducks are closely associated with water. Their primary habitats are a variety of wetland types; however they will also readily inhabit public parks. They frequently nest in well camouflaged nests on the ground; however, some species like the wood duck will nest in tree cavities. There are many omnivorous species of ducks that feed on aquatic vegetation, seeds, and invertebrates. Other duck species specialize in catching fish. Feeding styles also vary between species with diving and dabbling ducks.

Concentrations of ducks in urban areas can have several negative impacts. Accumulation of feces can contaminate water sources and degrade the quality of public parks. Large numbers of ducks feeding in agricultural fields can also create monetary loss for farmers. Ducks can also create a serious potential threat when they are present on/near airports. This danger is increased because they frequently travel in flocks and have dense, medium to large-sized bodies.

Several management options are available to keep ducks away from airports. Habitat modification is often the most effective of these methods. Elimination of open water or other wetland habitats from the airport will help reduce the presence of ducks. If this is not possible, exclusionary devices like wire grids can be constructed over appropriate bodies of water on an airport. Multiple harassment methods are also effective at moving birds off of a sensitive area.

Hawks (Buteos)

Buteos are a group of six medium to large-bodied raptor species found in North America. They have broad wings with deeply slit wing-tips that allow for effective soaring flight. Their large bodies make these birds more suited to open country, however, they can be found in forested areas. Buteos feed primarily on small mammals but will also eat other birds, reptiles, amphibians, and insects. The frequently hunt from perches or by soaring high above the ground and have the ability to spot prey from a very far distance. Buteos commonly nest in trees or on rocky cliff faces.

The large body size of buteos creates the potential for severe damage to aircraft during a birdstrike. Buteos are often attracted to airports by foraging opportunities in the vegetated areas of the airfield. Airport structures also provide convenient perches for these birds to use for hunting. Habitat around the airport may also attract these raptors as foraging/nesting sites. Exclusionary devices like bird spikes can be applied to airport structures to help discourage raptor perching. Removing nesting sites and/or nests is often used as a way to reduce buteo presence at an airport. Reducing potential prey at an airport may also help reduce the attractiveness of these sites. Harassment of problem birds will also help move buteos off of an airport.

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Eagles

Bald and golden eagles are two iconic raptors in North America. Both birds are two of the largest raptors, with only the California condor reaching a greater size. Along with their size, adult golden eagles can be identified by their brown bodies and tawny heads. Juveniles golden eagles are brown throughout the body with a white base to the tail and white patches on the wings. Golden eagles are common in western North America but rare in the east. They prefer open, mountainous terrain, often nesting on rocky outcroppings. Golden eagles feed primarily on medium size mammals like rabbits and prairie dogs; however, they are capable of taking much larger prey like ungulates. Adult bald eagles are very recognizable by their bright white head and tail and brown bodies. They are also the national emblem of the United States. Juveniles are variably pattered with brown and white throughout the body, taking five years to reach adult plumage. Bald eagles are opportunistic feeders, eating large birds, mammals, and carrion. However, their preferred food source is fish. They frequently nest in the largest trees in an area or rarely on cliff faces, using the same site each year.

The large body size of eagles creates the potential for severe damage to aircraft during a birdstrike. Eagles may be attracted to an airport because of nesting or foraging sites nearby. Removing nesting sites and/or nests is often used as a way to reduce eagle presence at an airport. Reducing potential prey at an airport may also help decrease the attractiveness of an airport. Any type of harassment or control performed on eagles or their nests requires a special permit under the Bald and Golden Eagle Protection Act.

Rock Dove (Pigeon)

Rock doves were introduced to North America from Europe in the early 1600's. Rock doves are strongly associated with urban areas, but can also be found near farmland and rocky cliffs. They feed on discarded food as well as seeds and fruits.

Rock doves are larger and heavier than the mourning dove. They have many different color variations, however, the majority of birds are blue and gray with two black bars on the wings. Many birds also have iridescent feathers on the throat.

Open hangars and other buildings at airports often attract rock doves as nest sites. Exposed food waste and vegetation that produces seeds can also attract these birds. Their larger body size and tendency to form flocks create a significant threat to aircraft.

Denying access to potential nesting areas may help repel rock doves from an airport. All that is required for a nesting site for these birds is a flat ledge to lay their eggs on. Keeping hangar doors closed and installing equipment like bird spikes on these surfaces can be highly effective at preventing nesting.

Gulls

Gulls consist of a group 23 species of birds in North America and 44 worldwide. They are colonially nesting birds that are typically associated with aquatic habitats. In recent years gulls have began using urban areas like flat rooftops for nesting sites and landfills for food sources. This behavior change has caused several species populations to dramatically increase.

Dense concentrations of gulls can have several negative impacts on an area. Water sources that these birds are utilizing can become contaminated from gull feces posing a human health risk. Gulls nesting on a rooftop can also structurally damage a building. Their feces is corrosive and nesting material may clog drains or be drawn into ventilation systems. Gulls also pose a significant threat to aviation due to their large body size and tendency to form large flocks.

Eliminating food sources is an effective method of making an area less attractive to gulls. This can be accomplished through covering trash receptacles and preventing feeding. Reducing and denying access to sources of open water also reduces site attractiveness. Gulls can also be dispersed through several harassment techniques. These techniques may also be more effective when reinforced with lethal control.

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Herons

Herons are large shorebirds that are found throughout North America. The most widespread of the six species is the great blue heron. Herons have long legs and S-shaped necks along with thick, pointed bills. Herons are typically seen standing in water waiting to catch passing fish. Because of this behavior they are closely associated with wetland habitats. However, herons will also feed on small mammals in an open field in this same manner.

These species often nest in trees in large colonies called rookeries. Concentrations of birds in these colonies can create several conflicts with the public. Accumulation of fecal matter below nesting sites can kill trees and other vegetation, damaging the habitat of other wildlife species. Large numbers of these birds feeding in one area can also deplete fisheries and damage fish farms.

Herons in the vicinity of an airport can pose a significant threat to aviation. They are large bodied birds that have the potential to cause severe damage during a collision. Herons are also slow-flying and may have more difficulty avoiding a collision. They may be attracted to an airport by open water and poorly drained ditches. Bodies of water surrounding the airport may also provide feeding/nesting sites where these birds will congregate. Elimination of open water and hazing/lethal control of problem birds are the most effective methods of managing these species.