The Turkey Vulture (Cathartes aura) is the most common vulture in the Americas. Despite the similarity in name and appearance, this species is unrelated to the Old World vultures of the family Accipitridae, which also includes eagles, hawks, kites and harriers. The American species are New World vultures in the family Cathartidae.

These birds are now placed in the order Ciconiiformes near the storks, but the taxonomy of the New World vultures is not settled. Undoubtedly, though, New World vultures are not very closely related to Old World vultures. The similarities are due to convergent evolution.

The typical adult bird is an average 76 cm (30") long with a 185 cm (6 ft) wingspan, and weighing 1.4 kg (3.1 lb). The sexes are similar, with the female being slightly larger. Their body feathers are mostly brownish-black, but the flight feathers on the wings appear silvery-gray beneath, contrasting with the darker wing linings. The adult head is small in proportion to its body, red in color with few to no feathers, and has a relatively short, hooked, ivory-colored bill. The immature bird has a gray head with a black beak tip.

Leucistic (sometimes mistakenly called "albino") Turkey Vultures are sometimes seen. The well-documented records come from the USA, but this probably reflects the fact that such birds are more commonly reported by birders there, not a geographical variation. In fact, even in the US, white Turkey Vultures (though they presumably always turned up every now and then) were only discussed in birder and raptor conservation circles, not scientifically studied.

Considerable interest was generated in the birding community of the West Coast by "Moby Vulture", a leucistic individual that roamed the San Francisco Bay area and Merced County in 2002 and 2003. This bird was creamy white all over, with some black feathers on the back; it seemed healthy and interacted normally with its black conspecifics. Since the mid-1990s, at least 4 white Turkey Vultures have been reported from the USA.

This bird got its common name by the resemblance of the adult's bald red head (and possibly its dark plumage) to that of the male Wild Turkey.

While soaring, they hold their wings in a V-shape and often tip "drunkenly" from side to side, frequently causing the gray flight feathers to appear silvery as they catch the light. They flap their wings very infrequently, often taking advantage of rising thermals to keep them soaring. The distinctive flight style, small-headed and narrow-winged silhouette, and underwing pattern make this bird easy to identify at great distances. A group of vultures circling in the air is a "kettle."

These birds soar over open areas, watching for dead animals or for other scavengers at work. Unlike most birds, the Turkey Vulture often uses its sense of smell to locate food. It will often fly low to the ground to pick up the scent of ethyl mercaptan, a gas produced by the beginnings of decay in dead animals. The olfactory lobe of its brain responsible for processing smells is particularly large compared to other animals. This heightened ability to detect odors allows it to search for carrion below the forest canopy.

The Zone-Tailed Hawk is a mimic of this species, resembling it in natural appearance and flying in formation with a group of Turkey Vultures, only to suddenly break off and ambush its prey. This is known as aggressive mimicry, and is of no help or hindrance to the vulture models.

This vulture feeds primarily on a wide variety of carrion, from small mammals to large grazers, preferring those recently dead, but may also feed on plant matter, shoreline vegetation, pumpkin and other crops, live insects and other invertebrates. Turkey Vultures can often be seen along roadsides cleaning up roadkill, or near rivers or the ocean, feasting on washed-up fish, another of their favorite foods.

The Turkey Vulture 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 but northern birds may migrate as far south as South America.

The nesting site is in a protected location: on a cliff, directly on ground in caves, crevices, mammal burrows, inside a hollow tree, in a thicket, or in abandoned buildings. There is little or no construction of a nest. Females lay two eggs, cream-colored, with brown spots around their larger end. Both parents incubate, and the young hatch at around 40 days. The adults regurgitate food for them and care for them for 10 to 11 weeks. If the young are approached in the nest, they defend themselves by hissing and regurgitating. The age of the young at first flight is about 9-10 weeks.

Often, small to large groups of these birds spend the night at communal roosts, and favored locations may be reused for many years.

Turkey Vultures roost in large community groups, breaking away to forage independently during the day.

Turkey Vultures are often seen standing in a spread-winged stance. This is called the "horaltic pose." The stance is believed to serve multiple functions: drying the wings, warming the body, and baking off bacteria.

The Turkey Vulture has few natural predators. Its primary form of defense is vomiting. These birds do not "projectile vomit," as many would claim. They simply cough up a lump of semi-digested meat. This foul-smelling substance deters most creatures intent on raiding a vulture nest. It will also sting if the offending animal is close enough to get the vomit in its face or eyes.

In some cases, the vulture must rid its crop of a heavy, undigested meal in order to lift off and flee from a potential predator. In this case, the regurgitated material has not yet been digested. Most predators will give up pursuit of the vulture in favor of this free edible offering.

Like storks, the Turkey Vulture often defecates on its own legs, using the evaporation of the water in the feces and/or urine to cool itself down, a process known as urohydrosis. Also, due to the nature of their diets, vulture excreta has a high uric acid content that acts as a sanitizer, killing any bacteria the birds pick up while traipsing on its food. This allows them a certain tolerance towards microbial toxins (such as botulism) and certain synthetic poisons that have been used to kill coyotes and ground squirrels.