This time last winter, Snowy Owls irrupted across the northern U.S., particularly the east and Midwest including Philadelphia. And biologists took the chance to outfit the birds with tracking devices. You can read about the surprising things they learned via Species on the move: Snowy Owl : BirdCast.
“As of mid-November, snowy owls had been reported by the dozens in the Northeast and Great Lakes, including birds as far south as Illinois and Maryland. One snowy owl that made it all the way to Oklahoma, unfortunately, was killed Sunday by a vehicle.” from the blog. Read more about Project Snowstorm.
Philadelphia Owls: A List of Species