H.J. Ruiz – Avian101

Black Vulture

The Black Vulture (Coragyps atratus), also known as the American black vulture, is a bird in the New World vulture family whose range extends from the southeastern United States to Central Chile and Uruguay in South America. Although a common and widespread species, it has a somewhat more restricted distribution than its compatriot, the turkey vulture, which breeds well into Canada and south to Tierra del Fuego. It is the only extant member of the genus Coragyps, which is in the family Cathartidae. Despite the similar name and appearance, this species is unrelated to the Eurasian black vulture, an Old World vulture in the family Accipitridae (which includes eagles, hawks, kites, and harriers). It inhabits relatively open areas which provide scattered forests or shrublands. With a wingspan of 1.5 m (4.9 ft), the black vulture is a large bird though relatively small for a vulture. It has black plumage, a featherless, grayish-black head and neck, and a short, hooked beak.

The black vulture is a scavenger and feeds on carrion, but will also eat eggs or kill newborn animals. In areas populated by humans, it also feeds at garbage dumps. It finds its meals either by using its keen eyesight or by following other (New World) vultures, which possess a keen sense of smell. Lacking a syrinx—the vocal organ of birds—its only vocalizations are grunts or low hisses. It lays its eggs in caves or hollow trees or on the bare ground, and generally raises two chicks each year, which it feeds by regurgitation. In the United States, the vulture receives legal protection under the Migratory Bird Treaty Act of 1918. This vulture also appeared in Mayan codices.

The black vulture is a fairly large bird of prey, measuring 56–74 cm (22–29 in) in length, with a 1.33–1.67 m (52–66 in) wingspan. Weight for black vultures from North America and the Andes ranges from 1.6 to 3 kg (3.5 to 6.6 lb) but in the smaller vultures of the tropical lowlands it is 1.18–1.94 kg (2.6–4.3 lb). 50 vultures in Texas were found to average 2.15 kg (4.7 lb) while 119 birds in Venezuela were found to average 1.64 kg (3.6 lb). The extended wing bone measures 38.6–45 cm (15.2–17.7 in), the shortish tail measures 16–21 cm (6.3–8.3 in) and the relatively long tarsus measures 7–8.5 cm (2.8–3.3 in). Its plumage is mainly glossy black. The head and neck are featherless and the skin is dark gray and wrinkled. The iris of the eye is brown and has a single incomplete row of eyelashes on the upper lid and two rows on the lower lid. The legs are grayish white, while the two front toes of the foot are long and have small webs at their bases. The feet are flat, relatively weak, and are poorly adapted to grasping; the talons are also not designed for grasping, as they are relatively blunt.

The nostrils are not divided by a septum, but rather are perforate; from the side one can see through the beak.The wings are broad but relatively short. The bases of the primary feathers are white, producing a white patch on the underside of the wing’s edge, which is visible in flight. The tail is short and square, barely reaching past the edge of the folded wings. The subspecies differ in size according to Bergmann’s rule, and the amount of white underwing coloration also varies.

Like other birds with scavenging habits, the black vulture presents resistance to pathogenic microorganisms and their toxins. Many mechanisms may explain this resistance. Anti-microbial agents may be secreted by the liver or gastric epithelium, or produced by microorganisms of the normal microbiota of the species.

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