Black vultures deserve a better reputation
The most abundant buzzard across the United States is still the turkey vulture, which sports pink skin on its head, a long tail and a V-shaped wing profile. But increasingly, it is the black vulture that we see, as this Southern carrion-eater expands its range and population size in the North due to climate change and other factors.
Black vultures are smaller, have a disproportionately short tail and possess a bare head that is black instead of pink. In contrast to the odor-sensitive turkey vulture, black vultures find dead animals visually, and especially by searching for turkey vultures that have sniffed out a rotten meal.
Black vultures are able to take over a carcass from their larger relatives through patiently waiting until a whole gang has been recruited, and then chasing off the turkey vultures as a group.
Many farmers blame black vultures for killing their livestock, especially newborn calves. Actual documentation has been hard to come by when researchers examine kills, and in most cases the black vultures have probably arrived post-mortem, but then are blamed for the kill. Black vultures also have an unexplained habit of ripping apart soft substances such as caulking or automobile windshield wipers. This may be due to boredom or exploratory behavior, and in Everglades National Park, an experimental vulture playground has been set up in one parking lot to give roosting vultures something to do other than vandalize vehicles.
There have been many eradication campaigns of black vultures in parking lots at recreation sites, as well as blanket permits granted to states by the federal government for farmers to shoot black vultures. Most farmers believe black vultures kill their animals, despite a lack of peer-reviewed scientific evidence.
As evidenced by growing populations, vulture-killing has clearly not caused the species to decline, but there is risk because black vultures require many years of maturing and experience before they will attempt to breed. Once they do breed, raising only one chick a year is the norm. In slow-breeding birds with this kind of life history, killing too many adults can lead to sudden population crashes, but clearly this has not happened yet — or black vultures would not be spreading gradually to the Canadian border.
It is important to remember, when cursing black vultures, that they serve an incredibly important role by vacuuming up bacteria and viruses from carcasses across the countryside and along all of our roads, and then dissolving these potential disease vectors in their strong stomach acid. We take for granted that carcasses will quickly disappear and be rendered into skeletons, but this will not be the case if vulture populations decline, as they have in much of the world.
Dan Cristol teaches in the biology department at William & Mary and can be contacted at dacris@wm.edu. To discover local birding opportunities, visit http://williamsburgbirdclub.org/.
