I saw the first of them on March 8, which has been the return date for these harbingers of spring for as long as we've lived in our Thorntown house. They typically return to Indiana a few days before the Vernal Equinox – some returning to longtime roosts and others stopping in transit to roosts farther north.
Gazing out my office window on this chilly windy afternoon, I can see a couple of them soaring lazy circles over the houses a block to the west.
The turkey vulture is second in size only to condors and eagles in the ranking of North America's birds and is a common sight in Indiana.
Neil Sabine, associate professor of biology at Indiana University East at Richmond, has been studying turkey vultures since the mid-1990s. He's trapped more than 200 birds and marked them and collaborated with the U.S. Air Force on a study on turkey vulture strikes on jet aircraft.
Turkey vultures don’t kill anything. They won’t touch anything that isn’t dead. Besides that, they will pass on dead carnivores like dogs, cats and coyotes, preferring to dine on dead herbivores like sheep, goats and cattle.
The Cherokees called the turkey vulture the “peace eagle” because it soars like the predatory bird, but does not kill.
They are about 25 inches from end to end with a six-foot wingspan. The average adult turkey vulture weighs in at 6 pounds.
The annual return of turkey vultures to Indiana, Sabine said, is temperature-dependent.
“If we have a hard winter they'll stay south longer,” he said. “This year we had a colder winter so the birds will come late because they move based on availability of food.”
If their food sources are frozen, they can't, get at the interior of a dead animal because they have weak bills. They need a food source that is soft and available to them, he explained.
After wintering in South or Central America, they return to northern nesting areas in two waves – transitory birds that may stop over in Indiana for perhaps two or three weeks before moving on – and permanent residents that will nest and remain in one particular area throughout the warm weather months, leaving as winter approaches in November or December.
“Some resident turkey vultures will stay all winter and go just far enough south where warmer weather is accessible, just kind of shifting with the weather,” Sabine said.
“Others will go all the way across the Caribbean to South America. Most of the birds we're seeing are from southern Mexico. The turkey vulture has the largest distribution of any bird in the world,” he said, noting that the birds are still expanding their range northward, moving into Canada.
In connection with the Air Force study, Sabine said turkey vultures can attain an altitude of nearly 1,000 feet if thermal updrafts are sufficient.
Bill Kohlmoos, president of the Turkey Vulture Society, wrote on his web site (turkeyvulturesociety.wordpress.com) that they have a rich social life, like to play aerial tag, and will invite other roosts to join them if they find a particularly large meal.
In California, he said, they’ve even been known to tell condors about major feasts and guide them to the scene.
“One lady wrote us that she has built a small wooden tower-like feeder in her back yard and puts out food for her friends each day. One day she noticed that after eating their breakfast, the vultures had gone down to the lawn in her yard and six of them were in a circle around a soccer-size ball left on the lawn by her grandchildren. The vultures were hitting the ball back and forth to each other by butting it with their head and beak. Each day thereafter they played this game. And although there were four balls of different colors, they always picked the orange one.”
He also learned that turkey vultures are affectionate and often make good pets. “When a bird is injured and taken into rehab he will become emotionally attached to his handler and follow him around and watch him, much like a pet dog. They love to bring an object to a person and then play tug-of-war.”
“A lady in Southern California wrote that she and her husband would drive their car five miles from town and take a daily walk in the country with their dog. A turkey vulture would join them, soaring above and watching them. And then one day at home she broke a leg and the walks were not possible for a while. One day she was in her back yard on crutches and there was her turkey vulture sitting on the fence, waiting to say hello. He had found her in a town of 12,000 people!”
Turkey vultures are covered by an international migratory bird treaty that makes it a federal crime to kill or injure them or to possess one without the appropriate permit as a wildlife rehabilitator.
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