I heard a talk by a crow expert at a wildlife rehabilitation conference many
years ago, and as I recall, he said that very large flocks (many hundreds
or more) are very common in winter. In particular, if I'm remembering
correctly, he said these flocks tend to be made up of juvenile males that
have left their family groups. Sort of like the street gangs of the bird
Is it common for crows to gather in such large flocks (there's one behind
my house, but it only has 10-15 birds)?