Skip Navigation

Species Search:
Ask an Expertthreatened and/or endangered

flocks of "blackbirds"

Several people in our high-rise condiominium a half-mile from the Potomac River occasionally see huge flocks of "blackbirds" flying by. Sometimes they fly by for minutes (?), so thick that the view out of our windows darkens. I know that blackbirds flock, particularly in winter, but I'm curious to learn more about this phenomenon. What species (or mix of species, as some sources suggest); do they roost together in such numbers or do smaller flocks join together as they fly; are the flocks transient or do they last for weeks or months; reasons for the behavior; etc.?

Birding Expert - George H. Harrison

Blackbirds usually join into large flocks for winter, and spend the season in middle America, which is where you are. The flocks often are a mixture of European starlings, common grackles, red-winged blackbirds and brown-headed cowbirds. They may use the same roosting location every night throughout the winter, or they may move around. But the flocks will break up in spring. GHH

New Search