The Fish Crow (Corvus ossifragus), a member of the Corvus genus, is a fascinating bird species endemic to the United States. Living primarily in coastal and tidewater regions of the Southeast, it has shown a remarkable ability to adapt to human presence, becoming a familiar urban bird in parts of its range. Superficially similar to the American Crow (Corvus brachyrhynchos), the Fish Crow is often distinguished by its unique vocalizations, described as a nasal "ark-ark-ark" or a begging "waw-waw." This article delves into the dietary habits of the Fish Crow, exploring its omnivorous nature and adaptability in various environments.
Identification and Range
Before discussing its dietary habits, it's essential to properly identify the Fish Crow. Measuring around 15 inches in length, it is a glossy black bird with a squared-off to slightly rounded tail, a stout, pointed black bill with a slight hook at the end, and strong black legs and toes. Stiff bristles cover its nostrils. While visually similar to the American Crow, the Fish Crow is slightly smaller with a more slender bill and feet. The most reliable way to differentiate the two is by their calls; birders often use the mnemonic, "Just ask him if he is an American crow," to remember the Fish Crow's distinctive nasal sound.
The Fish Crow is primarily found along the Atlantic and Gulf Coasts of the United States, from Rhode Island south to Key West, and west along the northern coastline of the Gulf of Mexico. Some birds in the northernmost part of its range may migrate in the fall. Its range has been expanding, and it has adapted well to various habitats, including fresh and saltwater lakes, rivers, beaches, marshes, and estuaries. It can also be found at the edge of forested areas near marshes and estuaries, as well as in agricultural fields, urban and suburban areas, golf courses, and wooded neighborhoods.
An Omnivorous Diet
Like all members of its genus, the Fish Crow is omnivorous, consuming a wide variety of plant and animal foods. This adaptability allows it to thrive in diverse environments and exploit various food sources. The fish crow feeds on the ground, around the edge of the water, and in shallow water. It also forages in trees for eggs and nestlings.
Specific Food Items
The Fish Crow's diet includes, but is not limited to:
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- Carrion and Garbage: As an opportunistic feeder, the Fish Crow readily consumes carrion and garbage, making it a common sight in urban and suburban areas. There is a Burger King and a Dominoes Pizza about a quarter mile or so from our neighborhood. Other restaurants are just a little further off. I suspect the Fish Crows head over there to choose their food.
- Crabs, Shrimp, and Crayfish: Its association with water leads it to consume crabs, shrimp, and crayfish, reflecting its common name.
- Insects: A wide variety of insects forms a significant part of its diet, especially during the breeding season when protein is essential for nestlings.
- Berries, Seeds, and Nuts: These plant-based foods provide essential nutrients and are particularly important during the fall and winter months.
- Bird Eggs and Nestlings: The Fish Crow is a known predator of other birds' nests, consuming eggs and nestlings of various species, especially those of colonial waterbirds.
- Turtle Eggs: The crows dig up turtle eggs, especially if residing by water.
- Peanuts: Fish Crows also like peanuts in the shell and suet. Fish Crows are too big to manage our feeders. But sometimes one will sit on top of the back yard shepherd’s hook pole where the suet feeders hang. It will make the nasal “Uh Uh” call. If I’m around, I will say “Uh Uh” back. The first few times I did this, the Fish Crow thought about it for a while, perched on a few different spots to scope things out from different angles. Then she swooped in to pick up the treat and flew back to the back corner of the yard. These Fish Crows are not greedy about it like Blue Jays, who will often amusingly try to stuff multiple peanuts into their beaks at a time. The Fish Crows, even with their bigger beaks, take one peanut or one chunk of suet. That usually satisfies them.
Foraging Behavior
The Fish Crow exhibits diverse foraging behaviors depending on the available food sources. It usually forages in flocks and does most foraging by walking, especially on shores or in very shallow water, also in fields; sometimes forages in trees. It may carry mollusks up into the air, then drop them on rocks to break the shells. It feeds on the ground, around the edge of the water, and in shallow water. It also forages in trees for eggs and nestlings.
In suburban environments, Fish Crows have been observed engaging in unique behaviors related to food preparation. For instance, they may bring food to birdbaths, typically picking the deepest one available, and dropping the food into the water. They’ll take a few sips of water and leave. A while later, they will come back and eat the food. Sometimes they will only take some of it, coming back multiple times, apparently testing its doneness each time.
Impact on Other Species
The Fish Crow's predatory behavior can have a significant impact on other bird species, particularly those that nest in colonies. In colonies of herons and other waterbirds, if adults are frightened from their nests, Fish Crows may destroy many eggs. They are recognized as despoilers of other birds' nests, especially those of colonial waterbirds. They may specialize on raiding the nests of colonial waterbirds, including Double-crested Cormorants, ibis, herons, gulls, and terns, as well as solitary-nesting species such as rails, ducks, plovers, and songbirds such as Blue Jays, Northern Mockingbirds, Brown Thrashers, Common Grackles, and Red-winged Blackbirds.
Nesting and Reproduction
Understanding the nesting habits of Fish Crows provides further insight into their dietary needs and foraging behaviors. Fish Crows often nest in loose colonies, with a few pairs nesting in close proximity. The nest site is typically in an upright fork of a tree or shrub, ranging from very low in coastal growth of pines and cedars to quite high in deciduous trees in inland swamps; nest height may be 5-70' above ground or even higher.
The nest, probably built by both sexes, is a bulky platform of sticks and strips of bark, lined with softer materials such as grass, rootlets, hair, feathers, paper, pine needles, even manure. The female lays 4-5 light blue-green eggs with brown blotches. Incubation is by the female, possibly assisted by the male, for about 16-18 days. Both parents probably bring food to nestlings. The age when young leave the nest is not well known, but is probably 3-4 weeks.
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Conservation Status
The Fish Crow population has shown mixed trends. Fish Crow populations slightly increased between 1966 and 2015, according to the North American Breeding Bird Survey, and their range has expanded during this time. The species rates a 10 out of 20 on the Continental Concern Score. Fish Crow is not on the 2016 State of North America's Birds' Watch List. West Nile Virus killed many Fish Crows, as it did other crow and jay species, in the early 2000s, but the Breeding Bird Survey indicates that its numbers are rebounding. The range expansion of Fish Crows, which often raid nests, may affect some species of breeding birds, especially colonially nesting species. Although crows are protected by the Migratory Bird Treaty Act, because they have been regarded as pest species, states retained the right to allow hunting of them. Fish Crows are still hunted in some states.
Factors influencing their populations include habitat preservation and human impact. Efforts focus on preserving wetlands and coastal areas. Protected parks provide safe nesting spaces. Public awareness campaigns reduce human impact. Research programs monitor population changes.
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