Turkey Vulture - Taxonomy

Taxonomy

The Turkey Vulture received its common name from the resemblance of the adult's bald red head and its dark plumage to that of the male Wild Turkey, while the name "vulture" is derived from the Latin word vulturus, meaning "tearer," and is a reference to its feeding habits. The word buzzard is used by North Americans to refer to this bird, yet in the Old World this word refers to members of the genus Buteo. The generic term Cathartes means "purifier" and is the Latinized form from the Greek kathartēs/καθαρτης. The species name, aura, is Latinized from the Native Mexican word for the bird, auroura. The Turkey Vulture was first formally described by Linnaeus as Vultur aura in his Systema Naturae in 1758, and characterised as V. fuscogriseus, remigibus nigris, rostro albo ("brown-gray vulture, with black wings and a white beak"). It is a member of the family Cathartidae, along with the other six species of New World vultures, and included in the genus Cathartes, along with the Greater Yellow-headed Vulture and the Lesser Yellow-headed Vulture. Like other New World vultures, the Turkey Vulture has a diploid chromosome number of 80.

The exact taxonomic placement of the Turkey Vulture and the remaining six species of New World Vultures remains unclear. Though both are similar in appearance and have similar ecological roles, the New World and Old World Vultures evolved from different ancestors in different parts of the world. Just how different the two are is currently under debate, with some earlier authorities suggesting that the New World vultures are more closely related to storks. More recent authorities maintain their overall position in the order Falconiformes along with the Old World Vultures or place them in their own order, Cathartiformes. The South American Classification Committee has removed the New World Vultures from Ciconiiformes and instead placed them in Incertae sedis, but notes that a move to Falconiformes or Cathartiformes is possible.

There are five subspecies of Turkey Vulture:

• C. a. aura is the nominate subspecies. It is found from Mexico south through South America and the Greater Antilles. This subspecies occasionally overlaps its range with other subspecies. It is the smallest of the subspecies but is nearly indistinguishable from C. a. meridionalis in color.
• C. a. jota, the Chilean Turkey Vulture, is larger, browner, and slightly paler than C. a. ruficollis. The secondary feathers and wing coverts may have gray margins.
• C. a. meridionalis, the Western Turkey Vulture, is a synonym for C. a. teter. C. a. teter was identified as a subspecies by Friedman in 1933, but in 1964 Alexander Wetmore separated the western birds, which took the name meridionalis, which was applied earlier to a migrant from South America. It breeds from southern Manitoba, southern British Columbia, central Alberta and Saskatchewan south to Baja California, south-central Arizona, and south-central Texas. It is the most migratory subspecies, migrating as far as South America, where it overlaps the range of the smaller C. a. aura. It differs from the Eastern Turkey Vulture in color, as the edges of the lesser wing coverts are darker brown and narrower.
• C. a. ruficollis is found in Panama south through Uruguay and Argentina. It is also found on the island of Trinidad. It is darker and more black than C. a. aura, with brown wing edgings which are narrower or absent altogether. The head and neck are dull red with yellow-white or green-white markings. Adults generally have a pale yellow patch on the crown of the head.
• C. a. septentrionalis is known as the Eastern Turkey Vulture. The Eastern and Western Turkey Vultures differ in tail and wing proportions. It ranges from southeastern Canada south through the eastern United States. It is less migratory than C. a. meridionalis and rarely migrates to areas south of the United States.