To prevent bird-airplane collisions, safety officials need to understand the birds' point of view, according to a group of researchers who tested birds' responses to model aircraft to help develop methods for avoiding potentially fatal bird strikes.
Although dwarfed by man-made flyers, birds can damage airplanes and even cause them to crash. Lighting may be a critical factor in preventing these potentially fatal collisions, this study indicates.
Key to their study was the knowledge that birds don't see the world quite like humans do. For instance, Canada geese have wider lateral visual fields, meaning they can see farther to the sides of their heads, and they can see ultraviolet light, a part of the electromagnetic spectrum not visible to humans. [Infographic: Airplane Bird Strikes on the Rise]
It's a bird ...
The research team, led by Bradley Blackwell, a research wildlife biologist with the U.S. Department of Agriculture, focused on Canada geese, the species responsible for the highest number of aircraft-damaging strikes reported to the Federal Aviation Administration from 1990 to 2010. They looked at the aircraft through the eyes of these geese, using what is known about the birds' visual systems to analyse the visual characteristics of the model planes.
They found the captive Canada geese reacted most quickly to an approaching model aircraft with alternating pulsing lights. Meanwhile, the geese were slower to respond to an unlighted model and one designed to resemble a predatory bird.
Ultimately, they recommend mounting lights on aircraft that emit light in the ultraviolet/violet range of the spectrum to alarm the geese.
The finding that the standard radio-controlled aircraft alarmed the birds just like the predator model — a robot used to scare away congregating birds — is also important because it means they perceived the regular aircraft as a potential predator, Blackwell said in a statement.
"We can enhance this response via lighting," he said in the statement.
Wildlife striking planes
Bird-airplane collisions can have dramatic consequences, not all of them as fortunate as 2009’s "Miracle on the Hudson," in which a commercial pilot landed safely on the river after striking a flock of geese after taking off from LaGuardia Airport in New York City.
Since 1988, more than 219 people have died worldwide as a result of wildlife striking planes, according to Bird Strike Committee USA.
While efforts have focused on keeping geese and other birds away from airports, little has been done to keep birds away from planes once airborne, according to the researchers, who hope their work will help address this issue.
They caution that the radio-controlled craft used in this experiment are smaller and slower than regular planes, and that the geese tested were not free-ranging birds in flight. Nevertheless, their approach, which considers how birds perceive aircraft and behave in response, can clearly be used to improve the effectiveness of aircraft lighting to prevent bird-plane collisions, they write July 9 in the Journal of Applied Ecology.