Wisconsin birders are again being treated to a significant showing of snowy owls from Canada’s arctic tundra while resident American goldfinches are dominating backyard feeders in most areas.
“We’re seeing a significant number of snowy owls this fall and early winter, well above average,” said Ryan Brady, a state Department of Natural Resources research scientist who coordinates bird monitoring for the Wisconsin Bird Conservation Initiative. “So far, the flight is not as big here as two years ago, but we are on the western edge of a massive and possibly historic irruption from the Great Lakes east to the Atlantic coast, an event that’s making national headlines.”
Hundreds of the owls have been seen at many locations across the Eastern United States as far south as North Carolina and even Bermuda. Observers in Newfoundland also tallied more than 200 owls along a single 25-mile stretch of road.
About 55 snowy owls have been reported in Wisconsin through Dec. 8 via eBird, listserves, Facebook groups, DNR staff and other sources, Brady said.
This compares to about 115 owls by the same date during the large irruption of 2011-12, 30 to 35 owls in 2012-13 and none in 2010-11.
Wisconsin’s snowy owl sightings got off to relatively slow start, with only five individual birds reported before Thanksgiving. By early December, however, reports picked up rapidly, including five birds in Ashland and 11 in Green Bay.
Snowy owl movements are usually tied to populations of lemmings, a favorite prey whose numbers vary in Canada each year. One possibility is a very robust supply of lemmings, which allows the owls to raise many young. These young snowy owls then must disperse south to find their own territory and food.
A second possibility is the opposite: lemming populations are low, so owl reproduction was relatively poor and all birds young and old must fly south to find food.
While the 2011-12 irruption was believed to be due to a strong lemming population leading to more young birds dispersing southward, experts aren’t sure yet the reason for this year’s exceptional influx.
“Birders can maximize their chances of finding a snowy owl by checking suitable habitats such as coastal beaches, harbors and breakwalls, open grasslands and agricultural fields like the Buena Vista Wildlife Area, large wetland complexes like Horicon Marsh, airports and vast expanses of ice, which provide excellent tundra-like roosting habitat,” Brady said.
Snowy owls aren’t the only feathered friends putting on a show this December. American goldfinches are also gracing the state in above-average numbers, especially across the Northwoods and along Lake Michigan.
The birds are especially welcome given the scarcity of other irruptive winter finches this year, according to Brady.
“Last winter, Wisconsinites were treated to a spectacular flight of redpolls, siskins, crossbills and grosbeaks,” he said. “In contrast, all of these species are nearly absent from Wisconsin this year so far.”
Ample cone crops and fruit sources across the boreal forest are likely holding them there, he said.
The good news is these goldfinches will likely stay for the winter and often set up shop at bird feeders, providing great viewing opportunities, if not their namesake color.
Like many birds, goldfinches molt in the late summer and fall, losing their golden feathers for a more wintery brown. By late winter and spring, patches of yellow feathers appear successively until the bird again dons its splendid breeding plumage.
“Bird lovers can keep their goldfinches and other backyard bird happy by providing foods such as sunflower and thistle seeds, a heated birdbath and shelter in the form of thick shrubs, brush piles and trees,” Brady said. “Feeders and spent seed should be cleaned regularly to avoid the spread of disease.”