Turkey vultures may be short on looks, but they play a vital ecological role by disposing of carrion, thus promoting the recycling of nutrients and reducing the potential for disease.
Along with black vultures, they’re found year-round in the Lowcountry. The two types of scavengers may show up together at roadkills and dumpsters, but the species are fairly easy to tell apart.
Both birds have hooked bills and dark plumage, but turkey vultures have bald, red, turkey-like heads, in contrast to the bare, grayish-black heads of black vultures.
Turkey vultures have longer tails than those of black vultures, and they’ve got longer wingspans — up to 6 feet.
In flight, black vultures often alternate several strong wingbeats with short glides, but turkey vultures are masters at riding the thermals, circling slowly with wings spread in the shape of a V. Seen from below, the ragged, outstretched wings of a soaring turkey vulture are black on the leading edges, gray at the tips and trailing edges: a distinctive look.
Turkey vultures have an exceptional sense of smell, which they use along with vision to locate dead animals from afar. Studies have shown that foraging turkey vultures can detect the odor of decomposing flesh in miniscule concentrations—as small as a few parts per billion in the air.
An important clue is ethyl mercaptan, a substance released from carcasses in the early stages of decay.
Turkey vultures feed on a wide variety of carrion, from large mammals to small birds, fish, frogs, and sometimes invertebrates.
But they rarely, if ever, capture live prey.
Vultures can be gregarious, so they’re often seen soaring, feeding, or roosting in a group – more specifically called a “venue,” or “volt.” Or if the birds are flying, you’re seeing a “kettle” of vultures. If roosting, the group is called a “committee.” If feeding, it’s a “wake.”
In the Southeast, turkey vultures breed in spring and early summer. Nest construction is minimal: usually the female just deposits a couple of eggs within a tree hollow, rock crevice, cave, or other protected spot. Both parents feed the chicks by regurgitating food.
Regurgitation plays a major role in vulture defense, too. When threatened, a bird doesn’t hesitate to vomit. This behavior may repel the attacker, as well as lighten the bird’s stomach load should it need to take flight.
Even nestlings regurgitate if threatened by raccoons or other predators at the nest.
Why are turkey vultures characteristically bald? Traditionally, the lack of head feathers has been assumed to reduce the risk of soiling and disease associated with probing deeply into carrion. But new studies suggest that in at least some vulture species (there are 25 worldwide), a bare head may also keep the birds from over-heating.
Turkey vultures also have another way to deal with the heat: They urinate or defecate down their own legs, relying on evaporation to cool themselves down.
This behavior, along with carrion-eating and defensive vomiting, doesn’t make turkey vultures endearing to many people, but these big scavengers do have their fans. Some places, such as Weldon, Calif., and Makanda, Ill., have hosted celebrations – “vulture fests” – in their honor.
And the birds even have their own annual holiday, which originated in South Africa and England to promote public appreciation of the importance of vultures in the environment. It’s called International Vulture Awareness Day, and it’s now observed at various zoos and wildlife refuges around the world, including the Greenville Zoo and elsewhere in South Carolina.
This year it’s Sept. 2.
Vicky McMillan, a retired biologist formerly at Colgate University,lives on Hilton Head Island. She can be reached at email@example.com.