It is the time when the crows begin to form small roosting groups in the evening. Observers may note flights of crows all heading in one direction in late afternoon/evening or gathering in a group in the treetops. These gatherings are generally much smaller that the large winter communal roosts and we presume they serve as a sort of training ground for the sort of social interactions that occur later on when hundreds or thousands of crows gather in one location. One would also presume that the smaller roosts generally are comprised largely of crows closely related to each other by blood or mating and occupying territories adjourning or very close to each other.
According to Michael Westerfield,
“Roosting areas tend to be located where there are large, mature trees with open spaces in between. In cities and towns, cemeteries, college campuses, malls with adjacent trees, old rail yards, and older neighbourhoods and industrial areas, and the like tend to be favoured. If there is a river or other body of water nearby, its a definite plus. The crows generally settle on the branches of trees which have already lost their leaves, or on the uppermost branches of those that haven’t, so it is easy to spot their silhouettes against the still bright sky. At this time of year, the temporary roosts may be more loosely organised and spread out over a wider area that those in colder weather.
If there are crows in your neighbourhood throughout the year, it’s likely that there will be one of these temporary fall roosts nearby. The amazing thing about these roosts, and even some of the gigantic winter roosts, is that one can be fairly nearby and most folks will be totally oblivious to its presence. I suppose it has to do with the timing, when people are still at work, commuting home, or just settling in for a long autumn evening. Probably the most common reason folks notice crow roosts relates to crow droppings on their cars or sidewalks in the morning. If your car is clean, and you want to find your local roost, just take a walk in the late afternoon "“ with your ears free of noise making devices. Choose an area with large, old trees and open spaces. Watch and listen for crows passing by up above and move in the general direction in which they are moving and, if you are lucky, you might just arrive at the place the crows will choose to spend the night. You’ll know it when you get there!”