While birds, mammals and airplanes may seem to peacefully share the space at and in the vicinity airports, their co-existence can be burdened with extreme risk. In the case of a collision with an aircraft, a single animal has the potential to cause severe damage, which can lead to the loss of the aircraft, the crew and the passengers.

As air travel becomes increasingly popular, so grows the need for effective wildlife management at airports. Over the years aircraft noise has diminished while the number of aircraft movements has increased dramatically. Not only are the birds and mammals less able to avoid aircraft movements—there are fewer places left for these animals to find refuge.

The first reported bird-strike fatality occurred in 1912. The pilot suffered fatal injuries when his aircraft collided with a gull over the coast of California and crashed into the ocean. Since then, the number of reported wildlife strikes has increased significantly. In 2001, there were 941 reported strikes to Canadian aircraft. Although none involved human fatalities, huge costs were incurred with the strikes that adversely affected flight or inflicted damage.

All forward-facing aircraft parts are susceptible to damage when aircraft and wildlife collide. The engines of most large jet aircraft in service are certified to achieve a safe shutdown after ingesting a bird of 4 lbs. in weight. This certification does not support an engine that ingests multiple birds or a single large bird. As a result, multiple bird strikes require that the engine be reduced to idle thrust because of the vibration that can be caused by damaged fan blades. While the latest generation of jet engines is better able to withstand bird strikes, populations of many bird species are on the rise.

Although the windshields, nose, and empennage of transport category airplanes are designed to withstand some impact at cruise speed, they are susceptible to damage by large or flocking birds. This also applies to transport category helicopters and commuter category airplanes. Unfortunately, due to weight considerations, airworthiness standards for normal category airplanes and helicopters are virtually non-existent with respect to bird strike resistance.

Large flocking birds are considered to be the greatest threat to aircraft. This is because the impact of the bird strike is dependent on the mass of the bird and the square of the velocity of the aircraft. A large number of high mass birds being struck by a jet aircraft traveling at a high speed normally exceeds the design capability of airframes and engines. Statistics show that in the past 15 years the number of reported collisions worldwide between aircraft and birds over 2 kg in weight have risen steadily from 28 in 1980 to 265 in 1998- a significant increase. In addition, populations of some large, flocking birds, such as geese and gulls, have grown dramatically over the past 20 years as the birds become better able to adapt to the human landscape.

Ring-billed Gull populations in the Lower Great Lakes region have increased approximately 12% per year since the mid 1970s. In 1974 there were 5 nesting pairs of Ring-billed Gulls in the National Capital Region, whereas now there are over 6000 nesting pairs. Populations of migrating Canada Geese have doubled in the last 25 years, and many large race Canada Geese no longer migrate from the B.C. Lower Mainland Region or from southern Ontario. Resident Canada Goose populations in the Toronto area are doubling every five years. Geese thrive on the short grass habitats provided by parks, golf courses, and airports, and the remarkable adaptability of gulls has enabled them to make maximum use of waste disposal sites as a food source. The result of thesepopulation increasesis over 237 reported strikes involving gulls in Canada during 1995, and a 225% increase in damaging bird strikes to United Airlines' aircraft during the period January to March 1996 over the same period in 1995.

Transport Canada’s policy is to regard all wildlife on the airport as a potential hazard to aviation safety. As such, bird strike prevention begins in the airport environment, which is where over 80% of strikes occur during the takeoff and landing phases of flight. Although the prevention of bird strikes is the predominant focus of wildlife management plans, in some cases it is necessary to manage mammals such as deer and coyotes in order to maintain safe operations.

In order to develop an effective wildlife management plan, a risk analysis and ecological study should be conducted (link to bulletin 31). The study should be conducted over a period of one year to account for daily and seasonal bird movements. This will allow you to determine the species and number of birds on and in the vicinity of the airport. The emphasis of the program should be placed on those species that are a known threat to aircraft safety (link to bulletin 26).

The wildlife control program will include both active and passive control methods. Passive management techniques involve modifying the existing habitat to make it inhospitable to birds. This would involve removing or modifying attractants such as standing water, perching sites, resting areas or nesting areas. Active control techniques are those used by wildlife control officers to immediately disperse birds from the airport, including pyrotechnics, distress calls, propane cannons or falconry.

Birds are not only attracted to habitats that exist on the airport, but also to surrounding land uses. It is therefore essential for airport operators to be aware of the land uses that occur in the vicinity of the airport. Activities such as landfills, fish hatcheries, composting facilities and certain agricultural practices can attract birds that pose a threat to aircraft safety. Airport operators are encouraged to work with surrounding landowners and municipal governments in order to ensure a safe operating environment.

To ensure the highest quality of wildlife-strike statistics, it is crucial that agencies responsible for maintaining databases receive as much information as possible about every strike—even non-damaging strikes and near misses. While damage information is useful in quantifying the cost to the aviation industry, non-damaging strikes and near misses are of equal statistical significance when developing a complete picture of the risk at any particular location.

Despite progress made by North America’s aviation industry in reporting wildlife strikes, many continue to go incompletely reported or unreported altogether. Wildlife- management experts believe only 20% of all strikes are reported; reporting rates are likely lower in many developing countries where strike reporting is inconsistent or non-existent.

Transport Canada’s bird strike database is dependent on reports provided by pilots, airport operators, airlines, Nav Canada and the Department of National Defence. This information is important to engine and airframe manufacturers, airlines and all those involved in ensuring that the airport operating environment remains safe . It is essential to have an accurate means of quantifying the wildlife problem before effective management solutions can be devised and implemented.