Endemic to the United States and living primarily in coastal and tidewater regions of the Southeast, the Fish Crow has greatly expanded its range in the last few decades and is increasing in numbers. It has adapted well to living with people, becoming a familiar urban bird in parts of its range. Its ability to scavenge efficiently along shorelines adapted it well for human-modified environments—a major factor in the recent success of this bird.
Sympatric throughout most of its range with the similar American Crow (Corvus brachyrhynchos), the Fish Crow is often confused with its larger relative. The only reliable difference between the two is vocal: The Fish Crow sounds like an American Crow with a bad cold. Ecologically the Fish Crow is similar to the coastal Northwestern Crow (Corvus caurinus) of the Pacific Northwest; both share a nasal quality to their calls.
Like all other members of its genus, the Fish Crow is omnivorous, eating a wide variety of plant and animal foods. It is recognized as a despoiler of other birds' nests, especially those of colonial waterbirds. Outside the breeding season, Fish Crows often cluster in large groups to forage and congregate into large roosts to sleep. Breeding pairs hold small territories around nest trees, and in some situations they may breed semicolonially with several nests in close proximity. Once young are free-flying, Fish Crows leave their breeding territories and congregate at sources of abundant food.
This species remains little studied, despite its abundance. Concerning its nesting behavior, the only descriptions published in reviewed journals rely on limited samples, and most are from outside the core of the species' range (Meanley 1981; McNair McNair 1984a, McNair 1985b; McGowan 1990). Nearly all publications include only incidental observations, and much information published in state bird book accounts is unsubstantiated. Most citations of Fish Crow breeding biology date back to Bendire 1895 and have been passed along without critical review (e.g., Bent 1946a, Harrison 1975b, Baicich and Harrison 1997). Much remains to be discovered about the biology of this common and intriguing bird.