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For a listing of crow roosts in North America that have been reported to crows.net over the past decade, click here. Crow Roosts in North America
ROOSTSWhenever one speaks of crows, its wisest not to be too definite. The behavior of crows can vary widely from place to place. However, we can say that in many places, crows will gather in fall and winter to spend the night in large communal roosts containing several hundred to many thousand birds. Roosts as large as 200,000 or more birds have been reported. Communal roosts may remain in one location for a number of years or may shift from place to place in response to changing conditions. During the day, the crow population may be spread out over a very wide area, but perhaps an hour or more before dusk, birds will begin to fly towards the roost, collecting together into ever larger flocks as they get nearer. Generally, it seems as though most birds do not fly directly to the communal roost, but stop at nearby "staging areas". In some cases there may be several staging areas fairly near the roost. Often staging areas are in cemeteries or other areas where fairly open areas are surrounded by or interspersed with trees. Birds will fill the surrounding trees, hunt for food on the ground, and engage in general socializing. A roosting area may be virtually empty while nearby thousands of crows mill about in a staging area. As dusk approaches, the birds will abandon the staging area and gather in the communal roost. Often every suitable branch on every tree for a considerable distance will have a crow occupying it and there are constant alarms and mass flights and continual interactions of birds both in flight and in the trees. The noise level can be tremendous. As it grows dark the birds settle down and remain quite until dawn when they disperse again. Almost nothing is known about why crows form these communal roosts or of the dynamics of the populations involved. It appears that crows will travel considerable distances to a roost, but that not necessarily every crow in an area will travel to a particular roost every night. There is some indication that some individual crows may go to a roost some nights but not others. My own, thoroughly undocumented theory is that most of the crows at a roost on any given night are younger, unmated birds without their own territory. I also suspect that most of those younger birds come to the roost most nights while older mated birds with their own territory come only occasionally, if at all. According to this theory, the communal roost serves primarily a social function where birds challenge each other, find potential mates, and communicate, in one way or another, their individual and joint experiences. If this theory is correct, and most of the nightly inhabitants of a communal roost are young, non-breeders, it could explain why the destruction of birds at such roosts is always notoriously unsuccessful. In such a situation, even if you slaughter every bird in a roost, you leave the breeding population virtually untouched. Since competition for resources is now greatly diminished, the breeders are likely to be quite successful in replacing the lost population in a very short period of time. As I have said, most of the above is theory, supported by some observation. Little research on communal roosts has been done to date and your observations on the subject are greatly desired. Michael Westerfield Click on the following link for an excellent video presentation on crow roosts by the Humane Society: Humane Society Crow Roost Video. 
Spending the night in a roost can be a messy business if you're on a lower branch. In the photograph to the right, the white on the crow's wing is not reflected light, but the remains of droppings that fell from above. Crows that slept in large roosts are often spattered with white the following morning. POSTED: October 25, 2008. Fall Roosting Report by Michael Westerfield. As the weather grows colder and the leaves begin to fall here in Northeastern Connecticut, the local crows begin showing signs that the formation of the large winter roost is not far off in time. During the spring, summer and early fall, crow life tends to be centered around small family groups which forage together during the day and roost together at night, usually separate from other crow family groups. In winter, however, most crows will roost at night in large communal roosts, often containing many thousands of birds, who gather together from a wide geographical area. At this time of year, the behavior is often somewhere in between. When I walk outside anywhere from a half hour before sunset until the last light fades, if I pause and listen, usually I'll hear the calling of crows from somewhere in the vicinity. If I stand watching the sky, almost invariably I'll soon see small groups of crows flying overhead sometimes all heading in the same direction and sometimes seeming to mill about, riding the currents of air with an appearance partly of purpose and partly of pleasure. The interesting thing about watching these crows is that, unlike many flocking birds, starlings and the like, they don't move as a coordinated whole; each bird in a group is busy interacting with the others on an individual basis. A pair will come over and you'll see then swooping at and away from each other like children playing tag. One member of a group might break away and join another group or double back the way it came. When the weather is still mild, it seems that the birds here will gather in a number of smaller local roosts which will eventually coalesce into the larger winter gathering place. As one watches the crows shifting from place to place on a fall evening, I can't help thinking that some sort of democratic process is going on as the birds settle on an area in which to spend the night. There is a great deal of noisy flying about, with the birds settling first in one area, then some breaking away and moving to another nearby location. Individual birds may move back and forth between two or more groups and the whole mass of birds may rise into the air and settle again, or move, or divide into other smaller groups. This will go on until the light finally fades and, somehow, the whole flock has settled on one roosting area. 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 neighborhoods and industrial areas, and the like tend to be favored. 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 organized and spread out over a wider area that those in colder weather. If there are crows in your neighborhood 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! ROOST LOCATIONSIf you know of the location of a significant crow roost in your area, please send us the information.
For a listing of crow roosts in North America that have been reported to crows.net over the past decade, click here. Crow Roosts in North America
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