Black Vulture

STATUSLeast Concern

COMMON NAME (SCIENTIFIC NAME)Coragyps atratus

DIETCarrion

RANGEThroughout the southeastern and middle Atlantic region of the United States

HABITATOpen or partly forested habitats, often in close proximity to humans

Black Vulture

The Black Vulture has a body length of 60-68cm, a wingspan of 137-150cm, and weighs 1600-2200g.

Black vultures are large birds with dark coloration. Their body feathers are all black (often showing iridescent in the sunlight) except for patches on the underside of the wing. This light patch is caused by the primary feathers being whitish in coloration. The head and neck of an adult black vulture are dark gray, bald, and wrinkled while the juveniles are colored the same but often lack wrinkles. These birds have a dark colored beak with a lighter tip and their dark legs often appear whitish because they are coated in excrement. Black vultures hold their wings flatter and flap more often while soaring than their relatives, the turkey vulture. This in addition to the whitish underside of the primary feathers which looks like the bird is wearing white gloves, and a short, square tipped tail helps to distinguish between the two species while they are in flight.

The scientific name comes from korax, the Greek word for raven; gyps, which means a vulture; and from the Latin word atratus, meaning to be clothed in black, as in mourning. The Black Vulture has also been known as a Carrion Crow, Black Buzzard, and Jim Crow. (http://www.peregrinefund.org/subsites/explore-raptors-2001/vultures/blackvul.html)

Black vultures are generally silent birds although when they are in stressful situations they may make hissing noises.

Related To: Turkey vultures and other new world vultures

Habitat/Range:
Along with the Turkey Vulture, the Black Vulture is one of the most abundant New World vultures. In North America, Black Vultures are known to breed throughout the southeastern and middle Atlantic region of the United States and are often sighted in southeastern Canada. The species also breeds throughout Central America and much of South America. Black Vultures typically occur in open or partly forested habitats, often in close proximity to human settlements. Recently, this species has expanded northward in the eastern United States. Presumably, greater numbers of Black Vultures existed historically when waste disposal, ranching, and farming practices were less regulated. The Black Vulture is a highly gregarious species. Outside of the breeding season they often gather by the hundreds at communal roosts. Traditional roost sites, some of which are used for decades, often are occupied year-round. Other roosts are used seasonally in response to food availability. Roosts are thought to play an important role in the social lives of Black Vultures, both as places for juveniles and adult Black Vultures to interact, and as sites for foraging groups to assemble. There is some evidence that vultures find food by following conspecifics from roosts to carcasses. Turkey Vultures and Crested Caracaras often roost together with Black Vultures. (http://www.hawkmountain.org/raptorpedia/hawks-at-hawk-mountain/hawk-species-at-hawk-mountain/black-vulture/page.aspx?id=642)

Diet in Wild:
While these birds generally feed on carrion, black vultures have also been known to occasionally kill small live prey individually and sometimes go after larger live prey in flocks. These birds also consume vegetable and fruit matter as well as fish and garbage left by humans. Unlike turkey vultures black vultures tend to hunt by sight rather than smell. Because of this, these birds have been known to follow turkey vultures to food sources and then chase them away. These vultures often search for food along a road side where a road kill deer can provide food for several days. They will aggressively defend their meal from other scavengers.

Diet in Zoo:
Commercially raised and humanely killed mice. Frozen packaging not only ensures freshness but also cleanliness.  All of the Education Birds of Prey are not able to hunt on their own due to injuries, so live prey could never be offered. Diet enrichments ensure stimulation for the birds.

Predators:
Adults of this species are rarely preyed upon. The eggs and young of a black vulture are much more susceptible to predation due to black vultures’ preference to build ground nests. Typical nest raiders such as raccoons and weasels may extract the eggs or chicks form a nest.

Life Cycle/Social Structure:
Black vultures tend to gather in flocks and form strong social bonds with others of their species. They are monogamous and mate for life. They often spend even the non-breeding season with their chosen mates. When selecting a mate, the male and female go through flying courtship displays.

Once bonded and mated, a pair of black vultures will select their nest site and may even perch next to it for weeks to decide if it is an appropriate and safe location to raise young. These birds are ground nesters and will lay their clutch of eggs at the base of a large tree, in rock crevices, under rock overhangs, or any other site with suitable cover and little disturbances from humans and other animals. Black vultures rarely use nesting materials to line their nests.

Each clutch, laid once a year, generally contains 2 eggs. The pale green-blue eggs hatch between 32 and 45 days of being laid to reveal small chicks covered in buff colored downy feathers. Both parents share the responsibility of sitting on the nest. Chicks are fed regurgitated, liquefied food when they are first born but at about 2 weeks of age they also begin to receive some solid foods.

After the young have fledged and left the nest, they often remain with their parents until the next year’s breeding season. Even after leaving the parents, young vultures roost with older vultures and follow them to food. This allows the young to gradually learn to hunt for themselves by watching older, more successful vultures.

Life Span:
Wild black vultures can live up to 25 years in the wild although the average life expectancy is much closer to 5 years of age. In captivity, these birds my live up to 30 years old.

Interesting Facts:

  • Black vultures benefit from human disturbance and they are found in greater numbers near human populated areas
  • Like the Turkey Vulture, the Black Vulture’s numbers are increasing and its range is expanding northward in response to global climate changes.
  • New World vultures, like the black vulture are more closely related to storks.
  • The unusual bald head of the vulture is an interesting feeding adaptation. It prevents bacterial infection as the bird’s head is submerged in a carcass.
  • Vultures are known to defecate on their own legs. This behavior may benefit the bird by cooling it or by killing bacteria that may be on the bird’s legs.
  • On their own a Black Vulture can be dominated by the slightly larger Turkey Vulture at a food source. However, Black Vultures rarely travel alone and a flock of Black Vultures can quickly take over a carcass and drive the more solitary Turkey Vultures away.

Conservation Message:
The Black Vulture is very common but in 1972 it was blue-listed for two reasons: a decrease in numbers of suitable tree cavities for nest sites due to forest fire control, and widespread eggshell thinning from pesticides such as DDT. Its populations have rebounded and it now considered a pest species due to population explosion in urban centers.

DDT (dichlorodiphenyltrichloroethane) was a pesticide used in the United States, which was banned in 1972, that caused serious negative environmental affects.  It was spayed on crops to prevent consumption from pests and leached into waterways and soil substrates.  DDT was then absorbed into small organisms.  Once those small organisms were consumed by larger animals, it worked its way up the food chain to birds of prey like hawks, eagles, falcons, and ospreys.  DDT actually became more concentrated as it worked its way up the food chain. This is called biomagnification. It was absorbed into fatty tissue and didn’t kill the birds but created a calcium deficiency.  The lack of calcium caused the egg shells to be very thin so that when adults went to incubate their eggs the eggs would break.  For several generations these birds couldn’t reproduce.  This led to the ban of DDT in United States and Rachel Carson’s Silent Spring which helped lead the environmental movement.  DDT is still used in other countries and is still found in our ecosystems today.  Luckily a lot of Birds of Prey have made a come back.

Since they eat mainly carrion, black vultures are extremely susceptible to lead poisoning from animals shot with lead rounds. They are also frequently poisoned when they consume carcasses set out to poison other scavengers such as coyotes.

What Can You Do:
Make sure not to use lead ammunition when hunting. If an animal is shot and not found afterward, the lead can end up in the belly of a scavenger like the black vulture which can lead to the death of the animal.

Do not use poisons to control problem animals. Animals killed with poison often go off to die away from the site where they originally ingest the poison. These poisoned animals now become carrion for scavengers who then also ingest the chemicals. As the scavenger eats more and more animal containing poison, the poison builds up in their own system causing illness or death.

Do not litter. Throwing trash such as candy wrappers and even apple cores and banana peals along roadsides causes animals to come to these dangerous areas in search of food. When an animal is killed by a car it becomes a food item for black vultures and other scavengers who then also come to the roadside to eat and may in turn be killed by car strikes.

Bibliography:
http://www.allaboutbirds.org/
http://animaldiversity.ummz.umich.edu/
http://www.peregrinefund.org/
http://www.hawkmountain.org/