AMERICAN BLACK VULTURE

The 'Black Vulture' (American Black Vulture), ''Coragyps atratus'' is a New World vulture. 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.
Despite the similar name and appearance, this species is unrelated to Eurasian Black Vulture. The latter species is an Old World vulture in the family Accipitridae (which includes eagles, hawks, kites and harriers), whereas the American species is a New World vulture. It is the only extant member of the genus '''Coragyps'''.
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Contents

Appearance

Range

Diet

Reproduction

Status

Fossil history

See also

References

External links

Appearance

These are very large birds of prey at 65cm length and with a 1.5m wingspan. Their plumage is mainly glossy black; they have broad wings with white tips, a short tail and a featherless greyish head. In comparison with the Turkey Vulture, the Black Vulture flaps its wings more frequently during flight.
The subspecies differ in size according to Bergmann's Rule and the amount of white underwing coloration also varies. As they probably form a cline over their entire range, the species is often considered monotypic.

Range

These birds are found in open regions in the southeastern United States, Mexico, Central America and South America. They are usually permanent residents.

Diet

They eat mainly carrion and may scavenge at garbage dumps, but take also eggs and decomposing plant material, and can kill or injure new-born or incapacitated mammals. These birds on occasion forage in groups. They soar high when searching for food, holding their wings flat when gliding.

Reproduction

The female lays 2 or 3 eggs on the ground in a wooded area or in a hollow log or other cavity. Both parents incubate and feed the young, regurgitating food at the nest site.

Status

Though not having any natural predators, they have become scarce in some areas due to lack of suitable nesting habitat. In some other areas, e.g. Virginia, their numbers have increased to the point that they are perceived by some as threats to health and safety. They are known to regurgitate when approached or disturbed, which in birds, besides being a sign of nervousness, assists in predator deterrence and taking flight (by decreasing takeoff weight).
In Canada, Mexico and the United States, this species receives special legal protections as covered under the Migratory Bird Treaty Act of 1918.

Fossil history

From the Early to the Late Pleistocene a prehistoric species of Black Vulture, '''Coragyps occidentalis''' ('Pleistocene Black Vulture' or, somewhat in error, "Western Black Vulture"), occurred apparently all over the present species' range. This bird did not differ much from the Black Vulture of today except by its size, which was about 10-15% larger, and a relatively flatter and wider bill (Fisher 1944). It filled the same ecological niche as the living form (Hertel 1995), and indeed seems to have evolved into it by becoming smaller during the last ice age (Howard 1962, Steadman ''et al.'' 1994). Well documented from fossil bones, the genus ''Coragyps'' gives a rare glimpse in the evolutionary dynamics of two chronospecies. The final stages of this evolutionary transformation must have been witnessed by humans: a subfossil bone of the extinct species was found in an Paleo Indian to Early Archaic (9000-8000 years BCE) midden at Five Mile Rapids near The Dalles, Oregon (Miller 1957).
Fossil (or subfossil) Black Vultures cannot necessarily be attributed to the Pleistocene or the Recent species without further information: the same size variation found in the living bird was also present in its larger prehistoric relative. Thus, Howard (1968) separated the Mexican birds as ''Coragyps occidentalis mexicanus'' as opposed to the birds from locations farther north (such as Rancho La Brea) which constituted the nominate subspecies ''C. o. occidentalis''. The southern birds were of the same size as present-day North American Black Vultures and can only be distinguished by their somewhat stouter tarsometatarsus and the flatter and wider bills, and even then only with any certainty if the location where the fossils were found is known (Arroyo-Cabrales & Johnson 2003). As the Pleistocene and Recent American Black Vultures form an evolutionary continuum rather than splitting into two or more lineages, some authors (e.g. Steadman ''et al.'' 1994) include the Pleistocene taxa in ''C. atratus''.

See also

★ Turkey Vulture, ''Cathartes aura''

★ Californian Condor, ''Gymnogyps californianus''

References

★ 'Arroyo-Cabrales', Joaquín & 'Johnson', Eileen (2003): Catálogo de los ejemplares tipo procedentes de la Cueva de San Josecito, Nuevo León, México. ''Revista Mexicana de Ciencias Geológicas'' '20'(1): 79-93. [Spanish with English abstract] PDF fulltext

★ Database entry includes justification for why this species is of least concern

★ 'Fisher', Harvey L. (1944): The skulls of the Cathartid vultures. ''Condor'' '46'(6): 272-296. PDF fulltext

★ 'Hertel', Fritz (1995): Ecomorphological indicators of feeding behavior in Recent and fossil raptors. ''Auk'' '112'(4): 890-903. PDF fulltext

★ 'Howard', Hildegarde (1962): Bird Remains from a Prehistoric Cave Deposit in Grant County, New Mexico. ''Condor'' '64'(3): 241-242. PDF fulltext

★ 'Howard', Hildegarde (1968): Limb measurements of the extinct vulture, ''Coragyps occidentalis'', with a description of a new subspecies. ''Papers of the Archaeological Society of New Mexico'' '1': 115–127.

★ 'Miller', Loye (1957): Bird remains from an Oregon Indian midden. ''Condor'' '59'(1): 59-63. PDF fulltext

★ 'Steadman', David W.; Arroyo-Cabrales, Joaquin; Johnson, Eileen & Guzman, A. Fabiola (1994): New Information on the Late Pleistocene Birds from San Josecito Cave, Nuevo Leon, Mexico. ''Condor'' '96'(3): 577-589. PDF fulltext

External links

★ Black Vulture