SEATAC, Wash. - One of the biggest dangers for airplanes at Sea-Tac Airport comes in a small package.
That package has four legs – and fur.
The hundreds of acres of fields surrounding the airport have become the perfect habitat for the field vole, a small rodent.
In addition to being cute, the field vole is also an attractive food source for predators. During peak times at the airport, their numbers swell to more than 10,000, providing the perfect meal for all types of animals.
"They are the plankton of the flats," said Bud Anderson, a raptor biologist. "Everything eats them – Great Horned Owls, Red-tailed Hawks, coyotes, you name it."
Having animals around the runways, however, can prove dangerous for planes in the air and on the ground. While fences can keep large animals like coyotes out, there’s no surefire system to keep birds away.
"There's no way we can really teach them to avoid planes," said Mikki Verhover, a biologist with the airport. "It’s not in their capabilities to understand how fast a plane is moving. So if they detect a plane, by the time they detect it, it's already where they are."
When a bird strikes, it can do serious damage to an airplane. It can destroy an engine, rip into a wing, or go right through the windshield. In 2013, there were 11,315 reported bird strikes across the country, although only 601 caused any damage. Here is the FAA bird-strike database
Biologists use a wide array of deterrents to keep raptors away, including pyrotechnics and other scare tactics. While some resident raptors have learned to steer clear of the flight path, for young birds, the lure of the vole can be too much, so workers will try to relocate them.
The process begins with a series of raptor traps set up around the perimeter of the airport. When one is tripped, a satellite transponder sends a text message to a team of biologists. The birds are then examined, put in a pet crate, and shipped 80 miles north to the Skagit Valley.
The program has a unique agreement with the Bellair Airporter, an airport shuttle service. Each bird gets a seat on a van with other travelers. This process means a bird can be relocated within a matter of hours, minimizing crate time and stress.
Once the birds arrive in the Skagit Valley, they are weighed and measured. They also are given ankle bands or wing tags and their information is entered in a nationwide database
"We want to know where they go. We want to know where they show up. We especially want to know if they come back to the airport or not," said Anderson, who has been working with birds for half a century. “If they come back, then that tells us that maybe we need to move them further."
Raptors typically wander for the first two or three years of their life before finding a mate and settling down. Some of the birds that have been relocated from Sea-Tac have been spotted as far north as Nanaimo, British Columbia, and as far south as Sacramento, biologists said.
In the 13 years of the program, more than 686 birds have been relocated. Only seven have returned to the airport.
Anderson added that the Skagit Valley can be a paradise for raptors.
"Lots of food, open fields, no jets," added Anderson. "There are so many field mice and other sources of food like rabbits. They do very well here."