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. It is less easy to tell apart from the carrion crow (Corvus corone), but it enunciates its calls differently.

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.

On December 21, 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
Activity Patterns

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 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. In the air, especially when in pairs or small groups, American crows may be able to drive away their predators; for example, they might chase off birds of prey while defending their nests by plucking the predators’ wing feathers. The predatory bird, unwilling to risk its plumage (since this gives it maneuverability), will usually retreat.

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

Cultural Significance
Symbolism

American crows and their close relatives are a common staple in Indigenous American folklore and mythology, being particularly prominent in the Pacific Northwest region. In quite a few cultures from North America, the creator deity takes on the form of a corvid, while many other cultures depict the crow as a trickster or storyteller. Depending on the specific culture, crows may be the protagonist or antagonist of creation stories, shown as a being who plays pranks or relays knowledge to humans.

These stories have a strong basis in reality, since corvids are extremely intelligent (some species are comparable to non-human primates) and empathic birds. Their cleverness and creativity has been clear to humans since before the written word; many First Nations and other Indigenous Americans greatly respect the crows and ravens, paralleling similar practices in other cultures around the world. Crows are commonly seen as symbols of intellect in nearly every human society.

For much of the colonial history of the United States, European-Americans took a less positive view of crows. Their nature as opportunistic scavengers earned them an association with death, a belief that was already well-established in Europe. In addition, the European colonists brought with them prejudice against crows and ravens as agricultural pests who would steal food. During periods of history when witch trials were prominent, corvids were frequently linked to witchcraft. Today, superstition has become less prominent, and with the modern understanding of ecology and animal intelligence the crow enjoys a more respected position among European-Americans. Of course, this is only now just coming in line with the understanding and respect Native American peoples have had for crows all along.

In Captivity

The complex intelligence of the American crow, like that of most corvids, makes it difficult to keep satisfied in captivity; that and its common nature in the wild makes it a relatively rare domestic animal. Younger birds live in bigger flocks, preferring more social interaction than their adult counterparts (which usually live in pairs or small family groups). The adults are easier to satisfy socially. Since they are intelligent, they require frequent stimulation and dynamic environments; they are problem-solvers and can be kept entertained with puzzles and other toys. Since they will solve most puzzles eventually, their playthings need to be swapped out with some regularity to ensure they remain entertained.

Even wild crows can form bonds with humans. Since time immemorial, people have realized that crows appreciate friendly interaction and gifts such as food and shiny objects. Crows will often thank their human friends by gifting them valuable objects in return, and will make regular visits to people who show them kindness.

Science

The American crow is medically significant because it is an indicator species for the West Nile virus. This virus was first introduced to North America in 1999 by an air traveler returning from Africa, having been bitten by a mosquito. Since then, the American crow population has dropped by around 45%, though fortunately they are still very common throughout their range. These birds are highly susceptible to West Nile fever, the disease caused by the West Nile virus.

When the virus is introduced to a crow population, it may cause up to 72% of the birds to die in a single season, which is a stronger effect than other bird species. Epidemiologists and ecologists can study unusual death rates in American crows to determine where the West Nile virus is spreading. Since crows cannot directly give the disease to humans, this is a relatively safe way to study the disease. It is spread by mosquito bites; if a mosquito that has bitten an infected crow bites a human, that human can then become infected.

Politics

As traditional European-American agriculture developed into modern-day agribusiness, birds such as the American crow became viewed as pests since they may feed on crops such as wheat and corn. They can actually be beneficial to farms since they feed on smaller pests such as mice, but nevertheless were killed in great numbers by American agriculturalists for many years. Killing them for sport was also quite common, in addition to the extermination campaigns carried out by many states. Today, they are protected under the Migratory Bird Treaty Act of 1918.

The American crow is ranked at Least Concern by the International Union for Conservation of Nature. Population control is permitted in some areas where they are considered a nuisance, but one must check with local and state regulations before taking action to kill the American crow.

Resources

It is relatively uncommon for the American crow to be hunted for its meat or eggs, though they are technically edible. More often, their iridescent black feathers are collected for decorative purposes; Indigenous Americans have used crow feathers decoratively for many generations. Traditionally they could be collected after falling loose from the birds, but prior to the Migratory Bird Treaty Act many European-American people would kill the crows for sport. The killing of American crows was encouraged in many parts of the United States prior to the Act being written into law because the crows can eat cereal grains; however, they also feed on pests such as mice and insects, so their presence can also benefit farms.

On a more personal level, friendship with crows can bring a person interesting goods. Providing the crows with food they enjoy and otherwise being kind to them will earn their trust and appreciation, and many such good-hearted people find that their kindness is repaid with objects the crows consider valuable. Shiny objects and other trinkets are common gifts, though people have reported all manner of things being given to them by friendly crows in exchange for food. Beyond this, the companionship of these birds is often enjoyed by people throughout the United States. It is a relationship that has likely persisted for as long as humans have lived on the continent.

Safety

For the most part crows are not aggressive and will only react if threatened. Be mindful of parents during the nesting season; eggs are laid in the spring and young will spend the next month or so growing and maturing. Like any animal, the adults will be protective during this time. Give nesting crows respectful space so that they do not feel threatened by you, and do not pick up chicks that you might find on your property. They are probably learning how to fly, and their parents will not be far off. Interfering with their learning process is detrimental to their ability to survive as adults. If adult crows show aggression toward you, quickly retreat from the area and give them the space they need to feel safe and respected. They may warn you away by diving at you, but will rarely resort to clawing or pecking unless they truly feel as though you have threatened them. Should you come under physical attack, shield your eyes and the rest of your face while you make your retreat.

Above, we have mentioned how demonstrating kindness to crows will earn their friendship over time. The opposite is also true, and tends to happen much quicker. Harassing or harming crows will ensure that they view you as an enemy, and they may return your unkind behavior. Not only this, but a crow that has been harmed by you can communicate to other members of its species that you are not to be trusted, which can earn you harassment from crows you have never even interacted with before. They can even inform their offspring of you, which means you might have made yourself the enemy of many generations of crows yet to come.

By and large the American crow means you no harm, and recognizes you as a fellow intelligent creature. Treat it with respect and you will receive it in turn. These feathered neighbors are perhaps among the best-adapted of wildlife to humans in their environment, and coexistence is quite easy indeed.