Source: Birds of North America
There are seven species of new world vultures. Of these, the black vulture is one of most abundant. Black vultures are residents of tropical and warm temperate areas ranging from southern Canada to southern South America, and are native to Costa Rica. They live up to 10 years on average. The black vulture is a large bird with up to 5 inches of wing span, a short tail, and powerful wing beat. This species of vulture has a dark gray to black bald and wrinkled neck and head. It is black overall and has neat white patches underneath the wingtips, which can be seen easily while they are soaring in air. The short, squared tipped tail also serves as distinctive field mark. The white patches underneath the wings distinguish it from turkey vultures, which often occur in the same area with black vultures. Black vultures are scavengers, and are often associated with turkey vultures. The black vulture lacks a sense of smell, so they fly at high altitude above turkey vultures and keep an eye on them (turkey vultures have developed a sense of smell) and then follow them toward the food. They follow successful turkey vultures to carcasses and then aggressively chase them away. Great numbers of black vultures quickly gather at large food sources. While feeding, the species is aggressive and frequently chases off other scavengers including turkey vultures and crows. They feed on carrion of all types and sizes, including donkeys, raccoon, cattle and large mammals. They also capture live prey, most of which are small mammals and birds. They also prey on eggs, nestling and newborn livestock.
Black vultures do not make their nest; they lay eggs on bare ground in caves, hollow trees, brush piles, hollow logs and abandoned buildings. Pairs usually continue to use one nest site for many years as long as breeding is successful. Black vultures are monogamous and maintain long term pair bonds. The pair associate closely year round and may feed their young for as many as eight months after fledgling.
According to the IUCN, the vulture is the species of least concern. Black vulture were considered beneficial scavengers in the 1800’s. But in the early 20th century people become concerned about vultures spreading disease and they trapped, poisoned and shot them until the 1970s. Additional declines in the black vulture population occurred from 1940 to 1970 because of the use of DDT as a pesticide. When black vultures consume food containing DDT, the pesticide can accumulate in their fatty tissues, and eventually result in eggshell thinning and reduced reproductive success. DDT was banned in 1972. Subsequently, from 1970 to 2014, their population increased. Most populations of black vulture are currently healthy and stable. Black vultures benefit from human activities, including cattle rearing, fishing, and garbage dumps that provide increased food resources, and they decline in the areas where the available food supplies have decreased because of increased sanitation measures. Current threats include environmental contamination such as lead, mercury and insecticides, which can poison black vultures. Collisions with cars are another source of mortality. The loss of high quality nest sites also affects the species. Forestry practices that reduce the number of tree cavities force black vultures to nest at sites where they are more susceptible to predation.
The species is considered least concern by IUCN; it does not have major threats. But we can protect it from minor threats it is facing, for example by reducing contamination of lead, mercury, pesticides. Black vultures still face threats of illegal shooting in America, and this should be made a punishable offense. Actions should be taken to prevent the loss of high quality nest site. Finally, in the areas where black vultures are abundant, traffic regulation should caution drivers about the species’ vulnerability to reduce the collision of black vultures with cars.