He was not the only snowy owl to take up residence at a Pennsylvania airport. One at Pittsburgh International Airport was caught and relocated this week. Another, spotted at the Hazleton airport, is on the loose.
"Where they come from, there are no trees. It's flat and treeless," Weidensaul said. "They're looking for places that look like home."
There has been a massive migration south of snowy owls from northern Quebec, where the birds had an especially fruitful breeding season last year with an overabundance of lemmings, their favorite food.
Since late November, snowy owls have been reported as far south as Florida and Bermuda, Weidensaul said. A large number have taken up residence at the Jersey Shore, drawing bird watchers from around the region.
"This was completely unexpected. Suddenly, there were owls everywhere," he said.
He and other researchers put together a tracking project called Project SNOWstorm, which has raised more than $27,000 on the crowdfunding site Indiegogo.com.
When Philly was caught, he was fitted with a GPS unit. Maps of all his movements can be viewed at www.projectsnowstorm.org/maps/philly.