The turkey vulture (Cathartes aura) is the most widespread of the New World vultures. One of three species in the genus Cathartes of the family Cathartidae, the turkey vulture ranges from southern Canada to the southernmost tip of South America. It inhabits a variety of open and semi-open areas, including subtropical forests, shrublands, pastures, and deserts.
Like all New World vultures, it is not closely related to the Old World vultures of Europe, Africa, and Asia. However, the two groups strongly resemble each other due to convergent evolution.
The turkey vulture is a scavenger and feeds almost exclusively on carrion. It finds its food using its keen eyes and sense of smell, flying low enough to detect the gasses produced by the early stages of decay in dead animals. In flight, it uses thermals to move through the air, flapping its wings infrequently. It roosts in large community groups. Lacking a syrinx—the vocal organ of birds—its only vocalizations are grunts or low hisses. It nests in caves, hollow trees, or thickets. Each year it generally raises two chicks, which it feeds by regurgitation. It has very few natural predators. In the United States, the vulture receives legal protection under the Migratory Bird Treaty Act of 1918.
Names It is also known in some North American regions as a "buzzard" or "turkey buzzard," which in the Old World instead refers to members of the genus Buteo. In some areas of the Caribbean it is known as the "John crow" or "carrion crow."Turkey Vulture (Cathartes aura) . peregrinefund.org
Taxonomy
The turkey vulture received its common name from the resemblance of the adult's bald red head and dark plumage to that of the male wild turkey. "Vulture" is from the Latin vulturus ("tearer"), describing its feeding habits. The word buzzard is used by some North Americans to refer to this bird; in the Old World that term refers to members of the genus Buteo. The turkey vulture was first formally described by Carl Linnaeus as Vultur aura in his 1758 10th edition of Systema Naturae, and characterised as "V. fuscogriseus, remigibus nigris, rostro albo" ("brown-gray vulture, with black wing flight feathers 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 taxonomic placement of the turkey vulture and the remaining six species of New World vultures has been in flux.Remsen, J. V. Jr.; C. D. Cadena; A. Jaramillo; M. Nores; J. F. Pacheco; M. B. Robbins; T. S. Schulenberg; F. G. Stiles; D. F. Stotz & K. J. Zimmer. (2007). A classification of the bird species of South America. South American Classification Committee. Retrieved 2007–10–15 Though they are similar in appearance and have similar ecological roles, the New World and Old World vultures evolved in different parts of the world and from different ancestors. Some earlier authorities suggested that the New World vultures were more closely related to storks.Sibley, Charles G. and Burt L. Monroe. (1990). Distribution and Taxonomy of the Birds of the World . Yale University Press. . Retrieved 2007-04-11. More recent authorities maintained their overall position in the order Accipitiformes along with the Old World vulturesSibley, Charles G., and Jon E. Ahlquist. (1991). Phylogeny and Classification of Birds: A Study in Molecular Evolution . Yale University Press. . Retrieved 2007-04-11. or placed them in their own order, Cathartiformes.
However, recent genetic studies indicate that neither New World nor Old World vultures are close to falcons, nor are New World vultures close to storks. Both are basal members of the clade Afroaves, with Old World vultures comprising several groups within the family Accipitridae, also containing eagles, kites, and hawks, while New World vultures in Cathartiformes are a sister group to Accipitriformes (containing the osprey and secretarybird along with Accipitridae).
Distribution and habitat
The turkey vulture has a large range, with an estimated global occurrence of . It is the most widely distributed vulture in the Americas and rivals its cousin the black vulture as the most abundant raptorial bird worldwide. Its global population is estimated to be 18,000,000 individuals.Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxent Wildlife Research Center (2014b). Available from https://www.mbr-pwrc.usgs.gov/bbs/ It is found in open and semi-open areas throughout the Americas from southern Canada to Cape Horn. It is a permanent resident in the southern United States, though northern birds may migrate as far south as South America.
The turkey vulture is widespread over nearly all American habitats but they tend to show particular habitat preferences. It is most commonly found in relatively open areas which juxtapose with woodland, which are important both for nesting and roosting. Furthermore, turkey vultures in North America generally avoid enclosed forested areas that may hamper their ability to take flight and tend to often favor hill or low mountainous areas that make catching flight easier with less effort.Wright, A. L., R. H. Yahner, and G. L. Storm (1986). Roost-tree characteristics and abundance of wintering vultures at a communal roost in south central Pennsylvania. Raptor Research 20:102–107. This species can be seen over open country, including grasslands but are often absent from completely treeless areas such as some parts of the prairies or Great Plains.Johnsgard, P. A. (1979). Birds of the Great Plains: Breeding Species and their Distribution. University of Nebraska Press, Lincoln, NE, USA. Additionally, they may adapt to tropical and subtropical forests, shrublands, deserts and semi-desert, wetlands and foothills. Evidence indicates agricultural land is key habitat for turkey vultures, mainly pastureland or other low-input farmland for foraging and roosting but they tend to only occur ephemerally as flyovers around row-crop type agriculture.Graber, R. R., and J. W. Graber (1963). A comparative study of bird populations in Illinois, 1906-1909 and 1956-1958. Illinois Natural History Survey Bulletin 28:383-528.Butcher, G. S., G. P. Senesac, J. D. Lowe, D. L. Tessaglia, D. M. Nutter and R. J. O'Connor. (1991). A retrospective study of bird populations and agriculture: reproduction of birds in agricultural habitats. Maine: Univ. of Orono.Coleman, J. S., and J. D. Fraser (1989). Habitat use and home ranges of Black and Turkey vultures. Journal of Wildlife Management 53:782–792. Other manmade habitats can be used, with the species regularly seen over urban areas throughout its range, though they tend to use them more when not breeding, being unable to nest without appropriate habitats, and do not occur as an urban bird nearly as routinely as do black vultures in the tropics and subtropics.Gaby, S. R. P. (1982). Age-specific resource utilization by wintering migrant Turkey Vultures (Cathartes aura) in south Florida. Phd Thesis, Univ. of Miami, Miami, FL.Ferrara, J. L. (1987). Why vultures make good neighbors. Nat. Wildl. 25 (4; June–July):16-21.
This bird with its crow-like aspect gave foot to the naming of the Quebrada de los Cuervos (Crows Ravine) in Uruguay, where they dwell together with the lesser yellow-headed vulture and the black vulture.
Subspecies There are five subspecies of turkey vulture:
Image Subspecies Common name Description Distribution C. a. auraAntillean turkey vultureThe nominate subspecies. Occasionally overlaps its range with other subspecies. The smallest of the subspecies, but nearly indistinguishable from C. a. meridionalis in color. From Mexico south through South America and the Greater Antilles. C. a. jotaChilean turkey vultureLarger, browner, and slightly paler than C. a. ruficollis. Secondary feathers and wing coverts may have gray margins. It is found all the way to the Andes in Colombia, all the way to southern Argentina. C. a. meridionalisWestern turkey vultureA 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.Breeds from southern Manitoba, southern British Columbia, central Alberta and Saskatchewan south to Baja California, south-central Arizona, southeastern New Mexico, 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 Tropical turkey vulture Darker and more black than C. a. aura, with brown wing edgings which are narrower or absent altogether. 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. Found in Panama south through Uruguay and Argentina. It is also found on the island of Trinidad. C. a. septentrionalisEastern turkey vultureEastern and western turkey vultures differ in tail and wing proportions. It is less migratory than C. a. meridionalis and rarely migrates to areas south of the United States. From southeastern Canada south through the eastern United States.
Description
A large bird, it has a wingspan of a length of , and weight of .Poole, E. L. (1938). Weights and wing areas in North American birds. The Auk, 55(3), 511-517. Birds in the northern limit of the species' range average larger in size than the vulture from the neotropics. 124 birds from Florida averaged while 65 and 130 birds from Venezuela were found to average , respectively.Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001). CRC Handbook of Avian Body Masses, 2nd Edition (2008). John B. Dunning Jr. (Editor). CRC Press. . It displays minimal sexual dimorphism; sexes are identical in plumage and in coloration, and are similar in size. The body feathers are mostly brownish-black, but the flight feathers on the wings appear to be silvery-gray beneath, contrasting with the darker wing linings. The adult's head is small in proportion to its body and is red in color with few to no feathers. It also has a relatively short, hooked, ivory-colored beak. The irises of the eyes are gray-brown; legs and feet are pink-skinned, although typically stained white. The eye has a single incomplete row of eyelashes on the upper lid and two rows on the lower lid.
The two front toes of the foot are long and have small webs at their bases. Tracks are large, between in length and in width, both measurements including claw marks. Toes are arranged in the classic, anisodactyl pattern. The feet are flat, relatively weak, and poorly adapted to grasping; the talons are also not designed for grasping, as they are relatively blunt. In flight, the tail is long and slim. The black vulture is relatively shorter-tailed and shorter-winged, which makes it appear rather smaller in flight than the turkey vulture, although the body masses of the two species are roughly the same. The nostrils are not divided by a septum, but rather are perforate; from the side one can see through the beak. It undergoes a molt in late winter to early spring. It is a gradual molt, which lasts until early autumn. The immature bird has a gray head with a black beak tip; the colors change to those of the adult as the bird matures.