Join Wild Ohio as they look at A Gathering Of Crows
Why do crows congregate in large numbers to sleep?
http://www.birds.cornell.edu/crows/crowfaq.htm#roost
FREQUENTLY ASKED QUESTIONS ABOUT CROWS
Note: Most of these answers pertain to the American Crow, Corvus brachyrhynchos. Much of the information here is from my own research on crows in central New York; where I used other sources I have tried to reference the material. - Dr. Kevin J. McGowan, Cornell Lab of Ornithology.