Here, you see American crows starting to collect Friday (November 20) on one of their favorite roosting trees, a weeping beech.
The crows that have decided not to migrate are starting to form their winter communities here. In the spring, summer, and early fall, they maintain extended family territories that they defend against other crows.
As it gets cold and the leaves disappear, however, many nonmigrating crows from inland will come to the coast, somehow knowing that food-rich tidal zones usually are not buried in snow.
Leighton Archive Image
The formerly unneighborly resident crow families will create roosting areas with these inland birds and other “foreign” crows. They huddle through the winter nights with them. Why?
The leading theory is that crows sense their increased visibility (hence, vulnerability) in leafless trees. Their primary predators (other than humans) are great horned owls and other large raptors. Owls can see and attack crows better during clear winter twilight nights. The more crow eyes, ears, and sharp beaks available, the better that the birds can warn and defend themselves in winter. (Brooklin, Maine)