American Crow (S/F)

CrowThe American crow (Corvus brachyrhynchos) is a moderately large species of corvid found in the United States and Canada. The scientific name means “short-billed crow.” The species is present predominantly within the United States, and can be distinguished from the common raven (Corvus corax) by its smaller size. It can be told apart from the fish crow (Corvus ossifragus) because the fish crow ruffs out its throat feathers when it calls.

There are four subspecies known:

  • Corvus brachyrhynchos brachyrhynchos, the eastern crow, found in the northeast U.S.A. and Canada
  • Corvus brachyrhynchos hesperis, the western crow, found throughout western North America but not the Arctic, Pacific Northwest rainforests, or southern regions
  • Corvus brachyrhynchos pascuus, the Florida crow, found only in the U.S. state of Florida
  • Corvus brachyrhynchos paulus, the southern crow, found in the southern United States and northern Mexico
Description

The bird is roughly 16 to 21 inches in length (the tail makes up about 40% of this), with a wingspan of 33 to 39 inches. It is characterized by its all-black coloration, though its feathers exhibit iridescence. The legs, feet, and bill are all completely black along with the feathers. It may be told apart from its close relative the fish crow by its straight, somewhat thicker beak, which lacks a hooked end.

Its bill measures 1.2 to 2.2 inches long, though this varies by region; the body size also differs based on what part of North America it is found in. The subspecies of the far west and south are generally smaller than those found in the Midwest, east, and north. Body weight averages 11.1 to 21.9 ounces.

Growth

As with most birds, the young cannot fly; they are covered in a fluffy down until approximately 36 days old, at which point they gain their flight feathers. They reach breeding age at two years old, but typically do not leave their family’s nesting area to breed until four or five years old.

American crows live for six to eight years in the wild, but in captivity, can live up to thirty years.

Sexual Dimorphism

The male grows slightly larger than the female, but otherwise the American crow does not express any obvious sexual dimorphism.

Habitat
Preferred Habitat

American crows are adaptable and can be found in a wide array of ecosystems. They are known chiefly from forested habitat, but can thrive in many types of wilderness as well as managed parkland and urban areas. They do not live in the rainforests of the Pacific Northwest, or in tundras, where ravens may be found instead.

Isla Nublar

The American crow is not native to Isla Nublar and does not appear to have been introduced.

Isla Sorna

The American crow is not native to Isla Sorna and does not appear to have been introduced.

Other

American crows live throughout North America, found from the Atlantic to Pacific coasts; they are absent only from the Pacific Northwest’s rainforest environment and the northern tundra. Their southernmost range includes northern Mexico and Bermuda. They have also been sighted on the islands of Saint-Pierre and Miquelon, found off the Atlantic coast of Newfoundland and Labrador.

In December 2015, a single adult American crow (probably C. b. hesperis, based on locality and size of the animal) was sighted at the Mitchell residence in Madison, Wisconsin, U.S.A. Two adult American crows (also probably C. b. hesperis) were sighted in a zoo in northern California in July 2018.

Behavior and Ecology
Daily Activity

American crows are diurnal.

Diet and Feeding Behavior

As with most corvids, the American crow is an intelligent omnivore and will use a variety of methods to obtain food. It has good problem-solving capabilities, enabling it to take advantage of its environment when foraging. Some have even been known to create and modify simple tools to help them forage or hunt. The diet of the American crow includes invertebrates such as insects and worms, stranded fish, seeds, cereal grains such as corn and wheat, the eggs and babies of other animals, carrion, live mice and frogs, and human refuse. They are commonly sighted at landfills where they search for organic detritus.

During the autumn and winter months, they depend on acorns and other nuts for food.

Social Behavior

Family units form the basis of American crows’ social lives. A family consists of a mated pair and their offspring, with groups usually having about fifteen crows in them. The younger birds will stay in the nest until they are four or five years old, helping to raise their parents’ newest young.

Reproduction

These crows are monogamous and pair-bonds may last for life. The earliest eggs are laid in April, giving the American crow a head start over other birds. The eggs are round and have a shiny brown-to-gray marbled appearance, and are laid in nests made of sticks usually located in pine or oak trees. The female will lay three to six eggs at once, incubating them for about eighteen days; when the young hatch, their more mature siblings from previous breeding seasons will help the parents care for them. They are fledged after about thirty-six days, but will remain in the nest for several years even after reaching maturity.

Communication

The most commonly-heard vocalization from the American crow is a loud and quick cawing sound, usually repeated three times in rapid succession. They are usually seen bobbing their heads up and down with force while making this sound. However, the range of cries produced by these birds is much more varied, though not extensively studied. They are known to practice mimicry, copying the calls of other animal species.

The crow sighted in Madison, Wisconsin in 2015 could be heard mimicking another bird’s call, possibly a jay.

Ecological Interactions

American crows are predators to many species of small animals, including mice and frogs as well as many types of invertebrates. They also scavenge detritus and carrion, which helps to keep their local environment clean. Plants also fall prey to them, particularly cereal grains, though much of their plant-based diet consists of seeds and nuts that have already fallen.

They are mainly preyed upon by other animals as nestlings. Their young may be eaten by mammals such as raccoons and cats, as well as snakes. Adults are less vulnerable, but are sometimes killed and eaten by birds of prey. When feeding from carcasses, they are occasionally eaten by other opportunists such as bobcats and coyotes.

American ravens are known to be carriers of West Nile virus (Flavivirus sp.), which is transmitted by mosquitoes of the species Culex tarsalis.

Relationship to Humans

Like many corvids, the American crow can be considered a pest to humans because it feeds on crops such as wheat and corn. They may also benefit agriculture, though, as they will eat other, smaller pests such as mice. Nevertheless, American crows have been extensively killed by humans because of their pest status, but are now protected under the Migratory Bird Treaty Act of 1918. They remain very common all throughout their range.