Two years ago Snowy Owls staged a massive invasion into the Lower 48, and this year it looks like they are on the move again. In 2011 the invasion was continent-wide, with particularly large numbers in the Pacific Northwest and Great Plains, but numbers in the Northeast U.S. and Atlantic coast not particularly high. This year’s invasion looks quite different, with the center of focus (so far) being the Great Lakes and Northeast. Keep an eye out for these northern owls in open areas while you’re birding, and don’t overlook that white bump in the dunes, or on the peak of the house next door–it just might be a Snowy Owl. eBird is poised to track this invasion and compare it with previous ones, so please make sure to enter all sightings, and suggest that your birding friends do the same!
The map above shows the current (as of 3 December) point map for Nov-Dec 2013 (link to live map). Note how the invasion is restricted to the Great Lakes and the Northeast, but also with birds already reaching North Carolina and Bermuda! Some intrepid birders have racked up impressive totals, such as 12 along the New Hampshire coast 30 November or 8 around Boston on 3 December. Open the map link and zoom in to see just how strongly coastal this year’s invasion is. Almost every open and undisturbed beach seems to have a Snowy Owl right now. Some have been seen migrating over the ocean and others have been spotted on offshore buoys. Are these birds arriving direct off the water? Are they flying straight from Greenland?
Snowy Owls breed widely across the Arctic and move widely in search of resources suitable for breeding. These invasions tend to be driven by very good summer resources (lemmings primarily) in certain regions of the Arctic that lead to high breeding success. Many of the owls that move south are hatch-year birds (indicative of the high breeding success).