Vultures: Nature’s Curious Clean-up Committee
What does a kettle, a committee, and a wake have in common? These are the names we give to groups of vultures! Vultures (not to be confused with buzzards, which are actually European hawks) in flight are known as a kettle, a group of vultures feeding on carrion is said to be a wake, and if you observe a group of vultures roosting together, you’ve observed a committee, venue, or volt.
Because of their unique niche as carrion eaters, we might say vultures sit on the ecosystem sanitation committee! Vultures are scavengers that eat carrion, or dead animal flesh, and act as an ecological clean-up crew. In honor of Vulture Awareness Day, we are sharing how incredible these raptors are, and celebrating their important ecological role. Many people know of vultures from television or the news, where they are often negatively represented. However, as Allison Kreis, our vulture keeper here at the Desert Museum, reminds us, “Vultures are not the ‘evil’ and ‘dark’ creature that you see in media. They have very silly and mischievous personalities when you get to know them. Our black vulture acts very coy when he comes over to see what I am doing and he sometimes gets the ‘zoomies’ around the exhibit!”
Yes, vultures do eat other dead animals, but they rarely kill except in the case of the sick or dying. Their sharp, hooked beaks are great tearing tools, but vultures aren’t aggressive or even capable predators. They might give some humans an eerie feeling, but they are basically harmless, and are only interested in eating dead animals. Vultures are useful within our ecosystem, but they are also fascinating creatures in their own right: social, intelligent, and loyal.
Vultures in Arizona
Vultures can be easily identified by their characteristic bald heads, an adaptation that helps to regulate their body temperature and prevents bacteria and parasites from burrowing into feathers. Two species of vultures live in Arizona, the black vulture and the turkey vulture. The slightly larger turkey vulture is so named because of their superficial resemblance to wild turkeys. They have a wide range within the Americas, migrating up into southern Canada and New England during the summer breeding season. In addition to their keen eyesight, the turkey vulture can smell carrion from a mile or more away. This super-smelling ability is special within the bird world. In fact, turkey vultures have the largest olfactory (smelling) system of all birds!
Less gifted in the sniff department, black vultures will often follow turkey vultures to a meal and drive them off. Because vultures lack a voice box, or syrinx, their vocal abilities during confrontations are limited to hisses and grunts. Despite this competition during feeding, both species can be found cooperatively roosting together in groups. Bird enthusiasts in Arizona, try looking among the mesquite groves if you’re searching for vultures, as they often roost in stands of trees as well as manmade structures such as electricity pylons. Vultures like to nest on the ground, under cover, in places like tree stumps, caves, brush piles, thickets, and abandoned buildings. Look for them in the skies, soaring and circling magnificently (black vultures have powerful wingbeats while turkey vultures have more unsteady, teetering flight) on updrafts of warm air searching for their next meal.
Like many of our feathered friends, vultures are true valentines—they are believed to mate for life, and maintain social bonds with their family unit throughout their lives. Vultures feed their young for as much as eight months after fledging. Because of their weak legs, however, vultures don’t carry food back to their chicks, but will regurgitate it from their crop, a muscular pouch near their throat that expands in order to temporarily store large amounts of food. Now that’s a mealtime vulture chicks look forward to! As scavengers, vultures need to take what they can get when they can get it, and so will often gorge themselves and then take some time after feeding to rest and digest.
If we humans ate rotting meat, we would likely get very sick, and possibly even die or spread disease. Vultures are able to prevent disease from circulating in a population because of their iron stomachs—figuratively, of course! Vulture stomachs contain incredibly strong acids which eliminate bacteria and parasites that lead to such nasty stuff as botulism, cholera, rabies, and anthrax. Another way vultures stay clean and healthy is by urinating down their legs, so the uric acid in the urine kills accumulated bacteria. This behavior also allows the vulture to thermoregulate, as the urine acts like an evaporative cooler for their bodies.
While the feeding habits of vultures might not be exactly the same as ours, a world without vultures is not a world we should want to live in. Fortunately, despite a decline in the early 1900’s due to increased poaching and pesticide use, black vulture and turkey vulture populations in the United States are growing, unlike many of their African and Asian cousins. Besides human misunderstanding, their biggest threats are secondary and lead poisoning. You can help vultures and many other species of wildlife by choosing alternatives to rodenticide and other toxic pesticides that travel through the food chain, and if you’re a hunter, switch to non-lead ammunition.
So, the next time you see a vulture, thank it for helping to keep our environment clean!
References / Further Reading
Written by Elena Makansi.