It's a bird. It's a plane. It's ... a collision?
Accidents involving planes and wildlife are surprisingly common; thousands of them happen each year. In 2014, the Federal Aviation Administration counted 13,159 incidents in which a plane struck and killed at least one bird. There were an additional 509 accidents that involved other types of wildlife, including 25 incidents with white-tailed deer, 20 with turtles, and one improbable collision with an iguana in an airport in Key West.
The FAA maintains a database of all reported incidents of planes ingesting, colliding with, or striking various wildlife. It turns out to be a wealth of information about the surprising frequency with which planes collide with various forms of wildlife.
The database shows some good news, like the fact that commercial airliners collide with animals way less frequently than they used to just 15 years ago. Then there is some not-so-good news, like the fact that private airplanes are not seeing a similar decline. There's also some plain weird news — like that iguana collision, in 2014.
Birds are involved in the most collisions — but sometimes airplanes crash into reptiles, too
In the past 25 years, pilots and other aviation officials reported 156,114 wildlife strikes at 1,871 US airports.
From 2000 to 2014, the number of incidents that caused significant damage to aircraft decreased 24 percent, from 764 instances to 581. The year 2000 marked the height of damaging incidents reported to the FAA.
Experts say this is likely an underestimate of wildlife collisions, since the FAA does not mandate reporting. Dr. Richard Dolbeer, a wildlife hazard mitigation expert, conducted a report for the FAA and estimated that only 42 percent of all wildlife strikes get entered. Still, this marked a 19 percent increase from 1990 to 1994 reporting levels, which hovered at 20 percent.
Commercial planes hit more animals than private planes
Most aircraft collide with animals when the plane is either on the runway or preparing to take off or land. And there is some good news there: Since 2000, damaging wildlife strikes have declined for commercial planes on either the airport runway or when taking off or departing. Damaging strikes above 1,500 feet in elevation, which are often far more debilitating to aircraft, have not shown the same pattern of decline.
For smaller, noncommercial planes, the rate of damaging wildlife strikes hasn't declined at all and has actually increased at elevations greater than 500 feet (smaller planes, generally speaking, can't reach as high of altitudes as commercial jets). In the past 25 years, wildlife collisions totaled 67 commercial planes.
Most of those planes took off from small commercial airports. Often located in rural or secluded locations, which can be challenging when managing wildlife risks, private airports experience a greater rate of damaging strikes even though commercial planes make up a larger percentage of overall collisions with wildlife.
Turkey vultures cause the most damage to planes
In the past 25 years, the FAA with help from the Smithsonian has identified 518 species of birds involved in collisions, 41 species of land mammals, 21 species of bats, and 17 species of reptiles that were struck and killed by planes.
Unsurprisingly, the two government agencies have found that the more a bird weighs, the more likely it is to do damage to the airplane. Waterfowl, gulls, and raptors were found to have caused the most damage, while deer and coyotes accounted for the most destruction on land.
The mourning dove, American kestrel, and Killdeer are the most common types of birds struck by planes, but because of their small body mass the percentage of incidents that cause damage is minimal. Of the 6,873 incidents involving mourning doves, only 2.5 percent caused damage to the aircraft.
Increases in bird populations and air traffic may cause more accidents
Many of the bird populations cited in strike reports are on the rise, and, more worrisome, their numbers are increasing in urban environments, including airports. That can cause problems: For instance, the number of aviation accidents involving ospreys increased steadily from 1990 to 2014, as ospreys began to make up a larger percentage of the bird population in North America. In 2014, a record 29 strike reports filed involved ospreys.
The volume of air traffic in the US has increased as well, contributing to congested airways and increased probability of wildlife collisions. According to the FAA, air traffic in the US is predicted to grow at a rate of about 1.1 percent per year, from 24.5 million flights in 2014 to 30.2 million by 2030.
Wildlife, meanwhile, has become more threatening to more modern planes. Aircraft have become more efficient, with sleek two-engine models replacing three- or four-engine fleets. This means more of a risk if a wildlife collision damages one of the engines.
That was the well-publicized case of US Airways Flight 1549, which made an emergency water landing in the Hudson River after multiple bird strikes caused both jet engines to fail. Research has also indicated that birds are less able to detect and avoid modern jet aircraft with quieter turbofan engines.
The FAA is working closely with airports to reduce the number of aviation wildlife accidents by establishing wildlife perimeters around airports that keep out animals, and by supporting research efforts to develop better avian radar and bird migration forecasting tools. In addition, the FAA emphasizes the need for more detailed wildlife strike data, as it relies on its database to mitigate the damage caused by accidents with wildlife.