I have been watching (intermittently as I have time)several thousand crows as they gather prior to roosting for the night. Earlier in the fall they seemed to gather in the same areas at dusk, however, now I am finding those places devoid of crows and am finding large groups in other areas.
In your experience do crows change the location of the pre-roost sites? Could this be for safety in some way?
Are the crows in a particular pre-roost groups always the same ones? I have noticed that they seem to stream in from the same general direction each day.