2 December 2022
In mid November hundreds, perhaps thousands, of American robins (Turdus migratorius) were in the east end of Pittsburgh but left abruptly when the weather dropped below freezing on November 18th. By the 21st it was 17 degrees F and the robins were long gone.
Robins can cope with cold weather but not with frozen ground so they stay just south of the freeze line as winter approaches.
Those that nest in Canada and Alaska may leapfrog over the local slowpokes who wait for truly awful weather.
eBird distribution maps for June-July and December-February show that robins vacate the north to populate temperate zones in winter. June-July is dark purple with robins everywhere. In Dec-Feb they concentrate in the Pacific Northwest and northern California and in the U.S. southeast all the way to Florida.
Robins were on the move here in November. Now they’re south of us, wrapping up.
(photos by Robin Agarwal and Douglas on Flickr via Creative Commons license; click on the captions to see the originals)