GRAND RAPIDS, MI -- Live traps to catch snowy owls are now in place at Gerald R. Ford International Airport after staff was forced to shoot nine owls in the last two months as an aircraft safety precaution.

Since early December, snowy owls have shown up in force across West Michigan and the Midwest.

Wildlife biologists theorize that a disruption in their food supply in northern regions has forced them south.

Shooting the owls has been controversial and, in the New York area, became a hot-button issue when authorities revealed that owls were being shot at Kennedy International Airport.

Ford Airport spokeswoman Tara Hernandez said the influx of snowy owls into the area has been unprecedented and airport staff cannot compromise flight safety.

The owls are known to fly low and could fly into an aircraft engine, a wing or the cockpit window.

"As much as we can prepare for it, you don't expect something like this," she said of the owl population.

Ford Airport has a U.S. Fish and Wildlife agency permit to control the animals if they are deemed a safety hazard.

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A picture of a snowy owl in the airfield at the Ford International Airport (Courtesy: Gerald R. Ford International Airport)

So far, no planes have been hit by the owls, but wildlife experts say there have been close calls. In 2009, an airstrike with a snowy owl at Ford Airport caused $310,000 damage to an Airbus.

Aaron Bowden, a United States Department of Agriculture wildlife specialist, said he's witnessed owls at Ford Airport fly within feet of planes.

"They like to sit right at the edge of the pavement and it takes a lot to get them spooked, which generally means an aircraft taking off," he said. "They then fly directly across the runway, right about the same height as the nose or wing.

"I don't think it can be understood enough the seriousness of the hazard there is when they decide to take up residence near an airport," Bowden said.

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The Ford airport has long had a trap-and-release program for wildlife, including owls, and began talking about ways to bolster the trapping more than a month ago. Some traps for owls were at the airfield at the beginning of 2013, authorities said.

But Bowden -- who handles the program -- generally makes only one stop a month at Ford Airport and Tuesday, Jan. 21, was the first opportunity to set new traps. He set two traps on the airfield Tuesday.

The traps contain live bait, typically a pigeon, to lure the owl inside. Once an owl is captured, Bowden transfers the animal at least 50 miles away in hopes it will not return.

He's trapped about 20 snowy owls at airports across the region in the last six weeks and, in the past, has trapped other birds at Ford Airport including a red-tail hawk.

Like staff at Ford, workers at other airports in Michigan have shot the owls as well.

Hernandez said airport operations staff did their best in the last two months to scare off or "haze" the owls by honking horns and walking up to them. But in some cases, the owls simply return and the hazard continues.

This year is not the first year that snowy owls have been shot at Ford Airport. In 2009, two were shot, followed by one in 2010 and one in 2012.

Hernandez estimated the number of owls at Ford Airport is up to four times what normally might be seen there.

And while trapping is the preferred method, Hernandez said she cannot guarantee that more snowy owls will be shot if they pose a risk to planes and avoid being captured.

"I don't think we can ever promise that we won't do it again," she said.

Pete Butchko, the USDA wildlife services state director, said the owls like airports because they are used to living in wide-open tundra areas of the arctic circle, where few trees exist.

Airports offer a similar scenery.

He said he knows many in the public are concerned about shooting the owls.

"Because they are so uncommon here, I think they're very striking to people and sort of mythical," he said. "But the snowy owl is the largest bodied owl in North America. They present no small hazard to aviation."

E-mail John Tunison: jtunison@mlive.com and follow him on Twitter at twitter.com/johntunison