Originally printed in the May 20, 2003 edition of the Illinois Valley News
One sure sign of spring, which some people anticipate, is the arrival of Turkey Vultures to the Illinois Valley. Though not quite so romantic, or as regular, as the swallows returning Capistrano, but still a natural indicator of the season. They winter in Mexico and southern California and migrate up the Central Valley of California, over the Siskiyou Summit, and into the Rogue Valley in great numbers. Then they disperse into the smaller valleys while some continue north as far as southern Canada.
The common name, Turkey Vulture, is derived from its naked head being similar to the ground dwelling turkey. The scientific name Cathartes aura is obtained from “cathar”, Greek for clean, and “aur” , Latin for ear. This could refer either to its carrion eating habits or the lack of feathers on its head. Only mature vultures have a red head, the immature males and females have a black head and neck.
Another interesting tidbit is that studies of their excreted material in central California show about 25% of their diet is plant material. Vultures also eat small mammals such as moles and gophers and even many insects. While we’re on the subject, the fecal material is thought by some scientists to be antiseptic. They can consume rotting meat without harmful effects because the bacteria has been destroyed by their digestive system. This same white guano is not forced away from the body but dribbles down their legs and is thought to be a unique way of lowering the body temperature since they do not sweat.
Most birds have a syrinx, a structure in their throat which vibrates to produce sound. But the Turkey Vulture is lacking this structure. Therefore its only sound is a hissing noise when disturbed.
Vultures are easily recognized while they are soaring high above the valley floor searching for food. Their wings are extended with a slight V-shape as opposed to hawks and eagles which soar with a flat wing profile. They can soar for hours on rising warm air columns, called thermals, without flapping their wings. Their sense of smell is very acute in detecting dead animals. Natural gas maintenance workers often detect leaks in the pipes by watching where the vulture are circling. Vultures have another unique ability, similar to kangaroo rats, to survive long periods of time without water. They can extract water from the food they eat and recycle water internally.
Turkey Vultures were first recorded by scientists in 1839 in the Oregon area. This was by John Kirk Townsend who had come to Oregon with Thomas Nuttall in 1834. He often worked winters as a post surgeon for the Hudson Bay Company at Ft. Vancouver. One might suppose the Lewis and Clark Expedition would have reported them in 1805 – 1806. But they were only in Oregon from October to early April when the vultures are farther south. They do report killing a California Condor near the mouth of the Columbia River, showing their range was much greater than now. Today the condors are found only in small areas of southern California.
Lewis and Clark make no mention of Turkey Vultures being seen anywhere during the trip. Either the range has greatly increased since then, or more likely, they were so common and well known in the East that they didn’t bother to record them. By the way, one final tidbit, on May 14, 1804 the Lewis and Clark Expedition left St. Louis, Missouri to begin their trip. The year of 1803 was spent preparing the crew and collecting supplies as well as moving everything from Washington D.C. to St. Louis.