Master Naturalists: Turkey vultures are beneficial birds
By By Paul and Mary Meredith
July 3, 2014 at 2:03 a.m.
The Texas Quail Index demonstration we reported earlier continues. AgriLife Extension Agent Peter McGuill reports he examined the 24 false Quail nests we set out on McFadden Ranch in early June. After 2 weeks, 71 percent of the nests were undisturbed by predators. He will check again at a month from when we set them.
You see them on power poles, in trees and along the sides of roads scavenging and eating road kill. There is no mistaking this bird with any other. About 2 feet in length, adults weigh in around four pounds with warty, red, featherless heads, long, creamy hooked beaks and grayish-brown eyes.
A turkey vulture, scientific name Cathartes aura, which means "purifying breeze," has brown back plumage and is brownish-black elsewhere. A ruff of blue- or purplish-sheen feathers ring the neck. Legs are featherless and pale red. Blunt talons grace their chicken-like feet.
In flight, the wings are long with wingspans up to 6 feet, narrow with undersides of the wing tips and long tail appearing silvery from below. The outermost six feathers, which spread finger-like, are individually moveable control surfaces.
Wings tips ride above the body, forming a "v." Turkey vultures glide close to the ground - rarely flapping, rocking side to side - using the smallest air current to get lift. Their grace reminds us of a prima ballerina on pointe.
As a scavenger, this bird is almost unique. It has an extraordinary sense of smell. Flying, they scent decaying meat - following the scent upwind to the source.
Preferring fresh kill over rotten meat, the birds can detect the first stages of decomposition spanning long distances.
They are not aggressive feeders. They follow an established hierarchical feeding order to tear off bites on small kills.
When fights occur, it is usually black vultures driving off turkey vultures. Black vultures ride thermals of rising air high above turkey vultures and follow them to food.
Visible but secretive
Turkey vultures mature slowly, with adult plumage in two years and sexual maturity in five or more years - scientists are not sure; good breeding and life-span data is scarce. We do know they nest far from humans, preferring dark locations like tree cavities, enclosed rock ledges, abandoned buildings, etc.
They don't defend their territory and make no nest, laying two eggs from March to June on trash or a flat surface.
They are monogamous, bonding seasonally in a hopping courtship ritual. Pairs share egg incubation. Hatching in 30 to 40 days, chicks eat partially digested meat their parents regurgitate till they are fledgings at 70 to 80 days. A week later, they are independent.
What about the power poles, trees and cell towers?
Dr. Brent Ortego at the Texas Parks and Wildlife Department asked me the other day about why turkey vultures roost together. After discussing it a bit, he suggested we are seeing birds that are not sexually mature living socially away from predators.
There, they can catch the morning sun, partially spreading their wings to warm muscles and to dry dew from wing feathers before flying off to hunt.
Some biologists think this also exposes bacteria and pathogens they might get from carrion to ultraviolet sunlight, killing them.
Are they a villain?
Turkey vultures will never approach a live animal. Never. Myths about killing lambs or carrying off babies and small pets are false; they can neither hold prey nor lift in flight.
Black vultures may be more properly accused of preying on downed large animals but only rarely.
On balance, all six American turkey vulture subspecies are beneficial, reducing the amount of potentially disease-carrying carrion, from prairies, forests, beaches and roadsides from South America to northern Canada, following a seasonal north-south migration.
Why? Frozen carrion decays little, so it's hard to smell and harder to eat. We are lucky they're here year-round and also breed here.
Sources: allaboutbirds.org; wingmasters.net;birds.audubon.org; animaldiversity.ummz.umich.edu; txtbba.tamu.edu; Kirk, D. A. and M. J. Mossman.1998. Turkey Vulture (Cathartes aura). In The Birds of North America, No. 339; calliebowdish.com
Paul and Mary Meredith are master naturalists. Contact them at firstname.lastname@example.org.