When US Airways Flight 1549 made an emergency landing in the Hudson River in January after hitting geese, it turned the spotlight on so-called bird strikes — a longstanding problem of aircraft colliding with birds in flight. Airports try a lot of tricks to keep birds away, but now some researchers are shining light on a possible solution.
Bird strikes have killed more than 200 people worldwide since 1988, according to the U.S. Agriculture Department and the Federal Aviation Administration. The problem has cost the U.S. aviation industry hundreds of millions of dollars. And strikes have increased in recent years, as populations of large birds have grown.
Most of the time, when planes hit birds, it's at a low altitude near an airport. So airport managers and wildlife experts often focus on making the ground around airports inhospitable to birds.
Indiana State University biologist Steven Lima prepares a radio-controlled aircraft for flight. Scientists will fly the plane over the heads of Canada geese to test the idea that aircraft lighting may help warn birds away from approaching aircraft.
Indiana State University biologist Steven Lima prepares a radio-controlled aircraft for flight. Scientists will fly the plane over the heads of Canada geese to test the idea that aircraft lighting may help warn birds away from approaching aircraft. Robert Benincasa/NPR
But some wildlife biologists are considering a different possibility: warning birds away from aircraft in the sky by communicating with them visually.
At Plum Brook Station, a 6,000-acre, high-security government campus near Sandusky, Ohio, scientists are literally flying a plane at groups of geese and watching how they react. It's a radio-controlled model plane — a 9-foot wingspan aircraft that looks like a miniature Cessna.
Geese walk past one of several cameras that monitor them as scientists fly the plane around them.
Geese walk past one of several cameras that monitor them as scientists fly the plane around them. Robert Benincasa/NPR
The plane has white, pulsating LED lights mounted on the front, to test the idea that aircraft lighting can signal birds to get out of the way of an approaching plane.
It's a phenomenon that others have investigated less formally. One effort mentioned in a National Transportation Safety Board report in May was by Qantas Airlines. The Australian carrier reported a 10- to 40-percent drop in bird strike rates after they mounted pulsating lights on their 737s.
Agriculture Department wildlife biologist Brad Blackwell has been intrigued with the idea for years, and the model airplane project builds on earlier tests he conducted with a pickup truck.
"Vision is the primary sensory pathway in birds," Blackwell says. He and his research team hope to "play upon that sensory pathway, understand it and use the lights that are on the aircraft basically to buy time for the aircraft — and buy time for the birds."
To see how the birds will respond to the plane, the researchers lead four Canada geese into a grassy, fenced-off circle 56 feet across. The pen is surrounded by cameras that record the birds' movements from several angles.
Indiana State University biologist Steven Lima, who's also a model airplane pilot, powers up the aircraft. "Surprisingly, no one's ever looked at how planes approach birds and how they respond," Lima says. "It's never been done."
Working radio control joysticks from behind a tarp so he doesn't distract the birds, Lima flies over their heads a few times, then makes a rough, muddy landing.
The researchers will make multiple approaches at the birds, some with the plane's lights on, and some with them off. Later, they'll compare the responses of the birds to the various flights to see if the lights improved the birds' detection of the aircraft.
As the plane passes over them, it seems apparent that getting a rise out of these birds won't be easy. That may be because these particular geese are more gang than gaggle.
They're city dwellers, rounded up in a Cleveland park. Like many of the birds near airports, they're well-acclimated to human activity, and that's part of the problem.
"They're obviously not afraid of this aircraft," Blackwell says. "They're definitely not taking the initiative to get out of the way."
But biologist Esteban Fernandez-Juricic of Purdue University looks at video from a previous day's flights in a nearby trailer and sees some subtle movements that indicate the birds did regard the plane as a threat or predator.
"So the first reaction that you see is that the birds pull together and they group together very quickly as the airplane goes by," he says. "And the second reaction that we can see here is that some individuals duck down, right there."
The response is promising.
Fernandez's role in the research is to study the visual capabilities of the birds. Back at his lab at Purdue University, he'll test their eyes and dissect their retinas.
Understanding how the birds see could help the scientists work toward a recipe for aircraft lighting — including color and pulse rate — that could be used to warn various species of birds. One possibility may lie in ultraviolet lights, because birds tend to have better vision in the ultraviolet range.
"Humans have three visual pigments; birds have four visual pigments," Fernandez says. "And this visual pigment usually is in the UV range, the ultraviolet range. So birds can perceive more colors than humans can."
The researchers won't know the effect of the aircraft lights until they analyze the video recordings of numerous flights and several groups of birds. They're more than a year away from publishing their findings.