It's the flight risk that TSA agents can't screen for: a single bird getting sucked into an airplane's jet engine can wreak damage serious enough to require an emergency landing or, much more rarely, even cause the plane to crash. Known as "bird strikes," the incidents are surprisingly common, with an estimated 10,760 reported strikes at US airports in 2012 alone. But despite ongoing efforts to curb the prevalence of bird strikes, experts warn that they're likely to become more common — and that where strikes by some species are concerned, this winter might be particularly severe.

Unfortunately for birds and airplane passengers alike, avian species are often attracted to the wide open spaces that are characteristic of airports. "In general, birds that show up at airports are looking for three things: water, shelter, and food," says Archie Dickey, dean of Embry-Riddle Aeronautical University's College of Arts and Sciences who also developed an FAA database to document bird strikes. "So for them, an airport will often seem like the perfect habitat."

"An airport will often seem like the perfect habitat."

When a bird does find itself flying beak-first into an airplane's engine, the risk to human passengers can range from nonexistent to severe. Sometimes, Dickey says, the bird simply gets "chopped right up" by the engine's fan blades and travel continues as usual. A bevy of slightly more serious events cause more than 1,000 precautionary landings or delayed takeoffs each year. And in much more rare instances, like 2009's notorious Hudson River landing — blamed on a gaggle of Canada geese that got sucked into both of the plane's engines — the hazards can turn into a matter of life or death. More than 200 planes have been ruined by bird strikes since 1988, and an estimated 200 people have died in bird-triggered accidents in that same period, according to one recent study.

In an effort to minimize those dangers, aviation authorities have in recent years stepped up their strategies to keep birds away from the runways. Several airports, including major hubs like New York's John F. Kennedy International and Chicago's O'Hare International, employ full-time wildlife biologists tasked with monitoring local bird populations and keeping flocks at bay, while others contract the job out to wildlife consulting firms. Wildlife biologists track bird populations using radar, and then employ "harassment strategies" to spook them off. Noisemakers, lasers, and pyrotechnics are among the most common approaches, although some airports also play noises of either birds in distress or predators. "The problem is that birds are smarter than you'd think," Hickey says. "They can become acclimatized to a lot of what we throw at them."

Noisemakers, lasers, and pyrotechnics

When conventional efforts don't work, specialists will make changes to the airport's environment — eliminating standing water, killing off common bird prey, and reducing the accessibility of perch-friendly ledges — in an effort to make the habitat less desirable. And when all else fails, they'll resort to deadly tactics. Following 2009's Hudson River debacle, for instance, airport authorities in New York on several occasions euthanized hundreds of geese to prevent them from getting close to the city's airports. Such an approach elicited controversy just last week, when wildlife biologists at JFK were allowed to shoot and kill two snowy owls amid concerns that the enormous birds — whose wingspans can measure 5 feet — would fly into aircraft. Shortly after the uproar, officials announced plans to instead trap and relocate the birds, citing a desire to "strike a balance in humanely controlling bird populations at and around the agency's airports to safeguard passengers on thousands of aircrafts each day."

Such a balance, however, might be increasingly difficult to find. Where snowy owls are concerned, experts warn that we can expect more of them around some US airports this winter, largely because of a population boom that's pushed some snowy owls out of their native Arctic habitat. "They breed way the hell north in the high Arctic, hundreds of miles from a tree," says Kevin McGowan, an ornithologist at Cornell University. "They come south for a variety of reasons, and when they do, these open spaces at airports look the most familiar to them." This year, McGowan says, the birds have been driven out of the Arctic in surprising numbers — and airport authorities aren't quite sure what to do about it. "The approaches that work with other birds don't work with these guys," he says. "They're not easy to scare, and they just couldn't care less about people."

"They're not easy to scare, and they just couldn't care less about people."

And because of changes in both bird populations and airplane design, other species are also keeping airport authorities on their toes. Thanks largely to improved conservation efforts, birds that often pose a nuisance to airports — including Canada geese, great blue herons, and bald eagles — have experienced population bumps in recent years. Airplane traffic has also continued to rise, all while planes themselves become quieter and therefore tougher for birds to detect, Hickey notes. "Propellor planes or older models were much louder," he says. "Quiet planes might be good for neighbors who want less noise, but they aren't exactly good for bird strikes." And because reporting bird strikes to the FAA is optional, Hickey says that passengers looking for the safest flight option might want to peruse the agency's database carefully. "An airport that doesn't show any strikes might actually be the worst one of the bunch at managing birds," he says. "A responsible airport will report everything."