Black vulture

Name and taxonomy

William Bartram wrote about this bird in his travel book of 1791. He called it Vultur atratus, and also the carrion crow. His work does not count for naming, because he used the binomial system loosely. Johann Matthäus Bechstein published the same name formally in 1793. The word vulture comes from the Latin vulturus, which means a tearer. The species name atratus means clothed in black.

Emmanuel Le Maout placed the bird in the genus Coragyps in 1853. That genus name joins the Greek words for a raven and for a vulture. Three subspecies were once named, from the Andes and from South America. Their differences turned out to be clinal, so no subspecies are recognised now. Spanish and Portuguese speakers call the bird zopilote, gallinazo or urubu. Despite the shared name, it is no close relative of the Eurasian black vulture.

Evolution and relatives

New World vultures form their own family and are not close kin of the vultures of Africa and Asia. The likeness between the two groups is probably the result of a shared way of life. The black vulture is the only living member of the genus Coragyps. It sits at the base of the line that produced the turkey vulture and the yellow-headed vultures. That split happened about 12 million years ago.

A larger relative, Coragyps occidentalis, lived through the Pleistocene across the same ground. It was some 10 to 15% bigger, with a flatter and wider bill. A genetic study in 2022 showed that it grew out of the modern bird about 400,000 years ago. It took its larger body when it moved into high country. A bone of that species turned up in an early human rubbish heap in Oregon. A further fossil species from Cuba was described in 2020.

Appearance

This is a fairly large scavenging bird, 56 to 74 cm long. The wingspan runs from 133 to 167 centimetres, which is about 1.5 metres in a typical bird. Weight varies by region, from 1.18 kg in tropical lowlands to 3 kg further north. Fifty birds in Texas averaged 2.15 kilograms. In Venezuela 119 birds averaged only 1.64 kg. The tail is short and square, at 16 to 21 cm.

The plumage is mainly a glossy black. The head and neck carry no feathers, and the skin there is dark grey and wrinkled. The eye is brown, with one row of lashes above and two below. The legs are greyish white, and the two front toes are long with small webs at the base. No wall divides the nostrils, so daylight passes right through the bill from side to side. The wings are broad but short, and the white bases of the primaries make a pale wingtip patch.

The bare head is an adaptation to feeding inside a carcass. Feathers there would trap blood and body fluid and draw parasites. Black plumage stays visibly cleaner than a pale coat would. The short hooked bill strips meat from a body. A white bird was seen in Ecuador in 2005, among a flock of about twenty normal ones. Its skin looked a normal dark colour, so it was not an albino.

Habitat and range

The species covers the mid-Atlantic states, the southern United States and Mexico. It continues through Central America and most of South America. In the south the range reaches Peru, central Chile, Uruguay and all of Brazil. Stray birds turn up on Caribbean islands. The northern edge has pushed further into the Midwest and the northeast since 2000. GBIF holds occurrence records from 39 countries.

Most birds stay in one area all year. Those at the far north of the range may move a short way south in autumn. Others shift locally when conditions turn against them. The favoured country is open land broken by woods or brush. Open ground makes a carcass easier to see from the air.

The bird also uses moist lowland forest, scrub, grassland, marsh and pasture. Parts of the Brazilian Pantanal hold large numbers. Chaparral and heavily cut-over forest both suit it. Rubbish tips, sewers, slaughterhouses and city centres draw big flocks. A perched bird is most often seen on a fence post or a dead tree.

Diet and feeding

Carrion is the main food in wild country. Near towns the bird takes refuse, offal and any edible waste from a tip. It also eats eggs, fish, dung, ripe fruit and rotting plant material. It kills hatchling herons and seabirds at nesting colonies. Domestic ducks, skunks, opossums, small birds, lizards, snakes and young turtles all appear in its diet. By clearing dead animals it removes a source of disease from the landscape.

The black vulture has no sense of smell to speak of, so it finds food by sight. It also watches vultures of the genus Cathartes and follows them down. Those birds detect ethyl mercaptan, a gas given off by a body as decay begins. That sense lets them find a carcass under a forest canopy. A black vulture is aggressive at a meal and drives the larger turkey vulture off. A flock beats a single turkey vulture easily, because that bird forages alone.

This is the only New World vulture that preys on cattle. It harasses a cow in labour and mainly takes newborn calves, lambs and piglets. A very young calf lets the birds come close. The flock then pecks at its eyes, nose and tongue until the animal goes into shock. Black vultures in northern California have cut the umbilical cords of newborn sea lions. The same birds have picked ticks off resting capybaras and tapirs.

Like other scavengers, the bird resists the microbes and toxins in rotten meat. Vulture stomach acid reaches about pH 1.0, and that destroys most of what the bird swallows. Antimicrobial substances from the gut lining or from its own gut bacteria may help as well. A vulture can therefore eat meat carrying botulinum toxin or anthrax.

Behaviour and social life

The black vulture soars high on rising air while it searches. It holds the wings level in a glide, unlike the turkey vulture. The flight is a few quick flaps followed by a short flat glide. Short wings give it less lift than other vultures, so it flaps more often. It rides thermals up and then covers ground with little effort. It usually starts later in the day than the turkey vulture does.

The species is gregarious and roosts in large groups. Where the ranges overlap, the roost holds turkey vultures too. Family units form, and birds associate with close and distant kin. Groups forage together, which probably explains their advantage at a carcass. A disturbed bird brings up its last meal, which lightens it for take-off. The vomit is foul and corrosive, so it also puts off an attacker.

Like other New World vultures, the bird passes urine down its own legs. The water evaporates and cools the blood in the bare legs and feet. Uric acid kills bacteria picked up while walking on a carcass. It also leaves the legs streaked white, which is the mark of the habit. A vulture often stands with its wings spread wide. That posture probably dries the feathers, warms the body and bakes off bacteria.

Communication and senses

The black vulture has no syrinx, the organ that gives most birds a voice. It is therefore silent most of the time. An agitated or feeding bird hisses, grunts, or gives a low barking sound. Those noises are heard most while birds squabble over a body. Posture appears to carry most of its signalling, rather than sound.

Eyesight is the sense that finds food. The bird spots a carcass from the air, or spots other vultures dropping towards one. Its sense of smell is poor next to that of the turkey vulture. In courtship, several males circle a female on the ground with half-open wings. They strut and bob their heads while they circle. Black vultures have also been seen preening crested caracaras that bowed to invite it.

Reproduction and life cycle

The breeding season shifts with latitude. Florida birds may start in January, while Ohio birds wait until March. In Argentina and Chile laying can begin in September, and further north in October. Birds in Trinidad often wait for November, and birds in Ecuador for February. Pairs form after the courtship walk, and sometimes after a chase or a dive over the nest site. The species is monogamous and raises one brood a season.

No nest is built at all. The eggs go on the floor of a cave, a hollow log, a rock crevice or an empty farm building. Where no predators threaten, a pair will use bare ground under thick plants. A site is seldom more than 3 metres above the ground. Some pairs decorate the ground nearby with bright plastic, glass or bottle caps.

A clutch usually holds two eggs, and rarely one or three. Each egg is oval and measures about 7.56 by 5.09 centimetres. The shell is smooth and grey-green, bluish or white, blotched at the wider end. Both parents sit, and the eggs hatch after 28 to 41 days. Chicks hatch under a buff-coloured down, while turkey vulture chicks are white. Both parents feed them by bringing food back up at the nest.

The young stay at the nest for about two months. They fly well after 75 to 80 days. The oldest wild bird on record reached 25.5 years. Captive birds have lived to 21 years. One ringed wild bird was recovered at the age of 16.

Predators and threats

A grown black vulture has few enemies. Its size and its temper keep most hunters away. Eagles kill some birds in fights over food. The ornate hawk-eagle takes adults, though it is slightly the smaller bird. Both North American eagles have also killed black vultures.

Eggs and chicks are the vulnerable stage. Raccoons, coatis and foxes eat them when they find a nest. In 1972 the species went on a watch list in the United States. Fire control had cut the number of large hollow trees available for nesting. Pesticides such as DDT had also thinned the eggshells. Numbers recovered afterwards, and the bird is now treated as a pest in some cities.

Population and conservation

The IUCN lists the black vulture as Least Concern. The estimated population is 50 to 100 million mature birds. The global trend is unknown, and the species is far from any threatened threshold. A listing would need a fall of more than 30% over ten years or three generations. Numbers have still dropped in parts of the southeastern United States.

The loss of big hollow trees remains the clearest threat to nesting. United States law protects the bird under the Migratory Bird Treaty Act of 1918. Canada and Mexico protect it under their own migratory bird conventions. Taking, killing or holding one in the United States needs a permit. A breach can bring a fine of up to 15,000 dollars and six months in prison. Vultures elsewhere in the world have fared far worse, and nine of 22 species were critically endangered in 2016.

Relationship with humans

Cattle ranchers regard the black vulture as a threat to newborn stock. Few people see an attack happen, and vultures gather fast at any dead animal. It is therefore unclear how many reported losses the birds actually caused. Complaints also cover damage to buildings, foul smells and the noise of a large roost. The species is an increasing problem at the rubbish tips of large cities.

Large flocks near a tip are a hazard to aircraft. The airport at Rio de Janeiro is the best known case. Between 1990 and 2024 black vultures hit civil aircraft in the United States 382 times. Set against that, the bird clears road kill and other carcasses for nothing. That work removes carrion that could otherwise spread disease.

In culture and myth

The black vulture appears in a range of Maya hieroglyphs in the codices. The glyphs link the bird to death or mark it as a bird of prey. One common glyph shows the vulture attacking a person. Some glyphs clearly show the open nostril and the hooked bill. Others are read as this species because they are vulture-like, painted black, and lack the king vulture's knob. The bird carries none of the religious weight that the king vulture holds.

Across pre-Columbian America, vultures held a high place in religious images. Maya and Aztec art gave them both good and bad meanings. In Old World belief the vulture could stand for protection instead. The Egyptian goddess Nekhbet took vulture form, and queens wore a vulture crown. That contrast probably reflects how differently people read the same habits.

The black vulture is an important cultural symbol in Lima, Peru. It has appeared on two postage stamps. Suriname issued one in 1990 and Nicaragua issued another in 1994. Local names for the bird include zopilote in Mexico, gallinazo in the Andes and urubu in Brazil. Early American writers knew it as the carrion crow.