Have you noticed groups of crows flying overhead in the late afternoon, wheeling and diving? These are American Crows with a purpose. They're headed to their night roost, a giant slumber party. Up to 40,000 crows in one space is not uncommon for a winter-time roost. Gathering at dusk, crows land in a tree, then scuffle and squawk, filtering down through the branches.
The Crows' Night Roost

Carl Cook