By Brian Sullivan, project leader, eBird

Photo by GBBC participant Kim L. Graham, Ontario

March 9, 2006

One of the world's most spectacular birds irrupted southward this winter in unusually high numbers. For the first time in years, Snowy Owls moved far south of their regions of normal occurrence into the Pacific Northwest primarily, but also across Montana and the Great Lakes region. Snowy Owls made an incredible showing in the Great Backyard Bird Count, with 182 reported—a record high in the nine years since the count began.

This amazing Arctic breeder rarely occurs in the Lower 48. A few Snowy Owls typically wander well south of their normal range each year, but in years when prey availability is low, they move as far south as the United States/Canada border region, sometimes in numbers. Snowy Owls are diurnal hunters, and can be found actively foraging during the daylight hours throughout the winter. Birders often find Snowy Owls in coastal areas and agricultural habitats that approximate their favored tundra habitat.

This year was indeed unusual for Snowy Owls, not only in the numbers of birds reported, but in the concentrations of individuals. Ten or more Snowy Owls were reported from 4 locations across Washington, Montana, and Michigan. A record high count was also set for the most owls at a single location—18 at Pablo, Montana!

The big story was in the Pacific Northwest, where this winter’s numbers went through the roof. Three of the top ten reporting locations for this species were in Washington, with 35 reports! This is substantially different from previous years— five Snowy Owls reported in 2001, one in 2002, and none in 2003, 2004, and 2005. Similarly, numbers were very low in Montana in previous years, but 26 reports came in statewide this year! Michigan typically reports several Snowy Owls, but this year a remarkable 21 were found. Despite good numbers known to be present around Wolfe and Amherst Islands in Ontario, reports were lacking from that area.

This kind of movement to the south and subsequent concentration of individuals recalls the 2004–2005 invasion of Great Gray Owls into southerly regions. Like the great grays, the Snowy Owls seem to have taken a good bit of time to find their way south, but have congregated presumably around ample food resources available in relatively small areas.  There was even a report this winter of up to 30 Snowy Owls in a single field in Montana!

It will be interesting as the years go on to continue to document the ebb and flow of these large, northern owls as they find their way south.  Our knowledge of just why these invasions occur will increase as participation in the Great Backyard Bird Count and eBird continues to rise.

Report sightings of owls and other birds year-round with eBird. Visit www.ebird.org.

To learn more about Snowy Owls, visit the Online Bird Guide on the Cornell Lab of Ornithology’s All About Birds web site.