Pittsburgh — Four rare short-eared owls that landed at Pittsburgh International Airport this winter have been moved to a new home, and efforts are underway to trap and transfer perhaps a dozen more.
State-listed as endangered, the young raptors were relocated to a reclaimed surface mine about 50 miles away in another county, according to Tammy Colt, a biologist with the Pennsylvania Game Commission, which assisted the U.S. Department of Agriculture with the project.
The U.S. Department of Agriculture was the lead agency because airport property was involved and the birds posed a potential threat to airplane safety, Colt said.
At least a dozen owls began showing up last Christmas, presumably from Canada, said Colt, since resident “short-ears” are extremely rare in Pennsylvania, which is the southern-most part of their native range.
“We’ve seen short-ears from Canada in other winters, but not every year,” said Colt. “They may come here to escape snow cover in a really harsh winter that forces them to look in new places for food. It could be that young owls are seeking new turf.”
Although they are widely distributed worldwide, as a tundra species, they struggle in some places with diminishing habitat, as the open grasslands they prefer disappear to development. Short-ears stay low to the ground and hunt rodents.
“Airports and reclaimed strip mines have the grassy expanses they like,” Colt said. “We’ll see them group together in late afternoon around drainage ditches where they find a lot of voles, which is their preferred food.”
Although various traps have been used on short-ears in the past, this winter, Bobby Hromack of the USDA used a modified leg-hold device attached with wire cable to a pole, Colt said.
“It had a gentle spring and a rubber coating instead of teeth, so it wouldn’t break the owl’s leg.”
Hromack and his team watched from several hundred feet away and as soon as an owl got snared, it was banded and driven to the reclaimed mine, Colt said. “All of the trapped owls were hatch-year birds. The older birds were probably too wise.”
How many remain at the airport is unknown, but Colt said 13 were flushed in one night.
Because the trapped birds were banded, biologists will know if they return to the airport.
Fifty miles is the recommended distance for relocating an owl, said biologist Dan Brauning, the Game Commission’s wildlife diversity chief.
“It’s about an hour’s flight for an owl, and considered far enough away that it would be unlikely to return, although a snowy owl removed from the Philadelphia airport last year went back and got killed by a plane.”
That bird, nicknamed Philly, was part of a massive migration, or irruption, of “snowies” from the Arctic down much of the East Coast as far south as Florida in the winter of 2013-14.
Philly and a dozen other owls that decided to stay at Philadelphia International Airport were captured and relocated to eastern Lancaster County. All were outfitted with transmitters that allowed biologists to track their movements.
Philly returned to the airport within three days and got struck and killed by a cargo jet. The other owls ventured as far as Minnesota and Massachusetts.
“Snowies” are larger than short-ears, but dwell in the same flat grassland habitat and also stay low to the ground. During last year’s irruption, biologists speculated that a bumper crop of lemmings in the Arctic gave the snowies plenty of forage and they produced large clutches of eggs.