A road trip along any highway in Georgia will usually reward birdwatchers with the sight of vultures patrolling the skies above it. They feast upon the carnage caused by vehicles colliding into animals. Without vultures, roads would be littered with rotting corpses, attracting a plague of disease-carrying flies. In India recently, vultures were poisoned, causing a disastrous problem with sanitation. There are 2 species of vultures in southeastern North America–the turkey vulture (Cathartes aura) and the black vulture (Coragyps atratus). Both species nest communally, but the former flies in solitary pursuit of carrion, while the latter scavenges in flocks for dead animals. Though carrion makes up a majority of the diet of turkey vultures, they are also known to feed upon fruit and insects. Black vultures have an even more varied diet and will eat eggs, nestlings, newborn mammals, fish, fruit, and shit. They will actually peck out the eyes of newborn calves that then go into shock and die, providing a feast for the birds.
Scientists studying vulture diets in coastal South Carolina examined 176 pellets found under communal roosts of vultures. The 3 most common animal remains found in these pellets included in order white-tailed deer, striped skunk, and raccoon. Human garbage was found in 45% of the pellets. Vultures in this region basically live on roadkill and garbage.
Vulture populations in North America have likely increased over the past 2 centuries because the increasing population of humans has provided them with such an abundance of food. They are uniquely evolved to consume rotting flesh without ill effects and are able to take advantage of the carrion supply resulting from the habits of humans. They have heads and necks naked of feathers, so blood and gore doesn’t accumulate on them, and they are resistant to bacteria toxic to most other animals. However, they do prefer fresher meat. They nest on the ground, and all they need is a thicket where they can hide their eggs and young. They can live for decades.
Vultures may have been just as common or perhaps more so during the Pleistocene when they scavenged the corpses of megafauna. There were a greater variety of species then. The 2 species that live today occurred then, though some scientists consider the Pleistocene black vulture (Coragyps occidentalis) to be a different species. It was on average larger but otherwise identical to the modern species. In addition, massive teratorns that likely tore open freshly deceased mammoths and ground sloths soared in the sky. 2 species similar to Old World vultures ranged into parts of North America. Fossils of the American griffin vulture and another species have been found in southwestern North America, and they may have ranged into other regions of the continent. New World vultures, the black vultures and turkey vultures, were formerly thought to be more closely related to storks, but genetic studies determined they are most closely related to ospreys and secretary birds. Old World vultures belong in the family that includes eagles, kites, and hawks.
Refererence:
Hill, J., et. al.
“Diets of Black Vultures and Turkey Vultures in Coastal South Carolina, USA with a Review of Species Dietary Information”
Southeastern Naturalist 21 (1) 2022
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