Some estimates put the crow population at more than three billion in North America. These insecticides accumulated and are still found in natural food chains and in some bird species caused local reproductive failure or thin eggshells that break during incubation. However, it's speculative whether this is the case with crows. Each year, many crows winter in southern Pennsylvania, where weather conditions are relatively mild and food is abundant. Each day, crows fly in different directions from the roosts, feed and return at night.
Most birds usually leave and return along the same route each day.
The crow is classified by the Federal government as a migratory nongame bird. It's the only bird in this classification that may be hunted. Except in Hawaii, where crows are protected, they may be hunted during established seasons which may not exceed 124 days per year. States are prohibited from establishing seasons during the peak nesting period. Individual states set season dates and regulate hunting methods, bag limits, etc., under regulation set by the U.S. Fish and Wildlife Service.