Along with Turkey Vultures, Black Vultures are common year-round in the Lowcountry.
Look for these large black birds high in the sky, riding the updrafts and scanning the landscape below for the carrion that will be their next meal. Even from this distance, you can tell the two species apart if you study them carefully. While aloft, Turkey Vultures hold their wings in the shape of a “V,” but Black Vultures spread their wings fairly flat.
Underneath, Turkey Vulture wings are black on the leading edges and silvery gray toward the back. Black Vulture wings are all black except for silvery tips. Turkey Vultures soar lazily, teetering back and forth for long periods with few wing beats. Black Vultures alternate brief bursts of flapping with short glides.
Black Vultures are also slightly smaller, with a shorter wingspan (up to 66 inches) and a more compact tail. Their bald, wrinkled heads are grayish, in contrast to the bald red heads of mature Turkey Vultures. Both have sturdy hooked bills, used to tear apart and probe deeply within their rotting food.
Although Black Vultures have keen vision, they have a much poorer sense of smell, and often rely on Turkey Vultures to alert them to the presence of a meal. Turkey Vultures can pick up whiffs of ethyl mercaptan, a gas released from decaying flesh, from well over a mile away, at which point they start circling in on the carcass. Black Vultures then take off after them, arriving a bit late, perhaps, but still ready to compete aggressively, amidst grunts and hisses, for their share of the meal.
Since Black Vultures tend to forage in flocks, often family groups, they can easily displace a few Turkey Vultures from the feeding site.
Black Vultures are opportunistic feeders. They scavenge at landfills and dumpsters for fast food and rotting fruits and vegetables. They’ve been seen eating the fruits of oil palms and the eggs of some birds, turtles, and lizards. There are also reports of Black Vultures occasionally preying on live animals, including worms, insects, fish, small mammals, and even newborn livestock. Still, Black Vultures feed almost exclusively on carrion, and a central question is how they thrive on putrefying food without getting sick.
Recent studies have shown that their digestive tract is highly efficient at destroying a host of toxic microorganisms present in decaying flesh — that is, all but certain bacteria in the groups Clostridia and Fusobacteria. These persist in high concentrations in the vulture intestine and even assist the birds in digesting their food.
To humans, Black Vultures and their relatives may not score high on looks or feeding habits, but they play a vital role as avian garbage disposals. By readily disposing of dead and decaying animals, they help reduce the spread of disease and promote nutrient recycling in the environment.