I had never seen a turkey vulture when I was growing up along the river south of Story City. They weren’t common in Iowa in the 1960s. The book, “Iowa Birds,” published in 1984, still listed the turkey vulture as “a common non-nesting summer resident in wooded portions of the state.” They nest statewide now, and a careful scan of the sky on a summer day almost anywhere in Iowa is likely to reveal a turkey vulture or two soaring in lazy circles. The birds gained their name because of their naked red head and dark turkey-like feathers. They are easy to recognize even at a distance since they are the only large, dark soaring bird that hold their wings upward in a distinct V, called dihedral, as they soar. They also tip from side to side quite often as if unstable in flight. Eagles hold their wings flat. Red-tailed hawks hold their wings up at only a slight angle, are much smaller and are usually lighter in color.
The first local population of turkey vultures appeared near Ledges State Park in Central Iowa. They like roosting near big valleys and ridges, where winds passing up a slope cause what’s known as ridge lift. They are masters at sensing rising air and use it to stay aloft on motionless wings for hours at a time. Vultures prefer not to flap their wings if they don’t have to. They can also use thermals generated by rising warm air on sunny summer days to move far out over the agricultural flat lands as they seek carrion, which is anything that’s dead.
Turkey vultures are nearly unique among birds in having a highly developed sense of smell. They also have very good vision and use both senses to find their food. They can follow the faint scent of something even freshly dead long before they can see it. Most birds have little sense of smell. Great horned owls, for instance, are virtually immune to skunk spray and routinely take skunks as prey. Vultures play an important roll in maintaining a healthy environment. Their digestive system is able to safely cope with disease organisms often found in dead animals, enabling them to clean up things that could spread disease to other animals.
Vultures are often shown with the raptors in bird books; especially older ones. They eat meat and look a lot like hawks or eagles. Recent research has revealed that they are actually more closely related to storks, though. They don’t make nests, but like to lay their eggs inside something, whether it’s a cave, a hollow log on the ground or even abandoned buildings. A man recently told me about a vulture nest he’d seen in an abandoned farm house near Boone. The birds entered through a missing upstairs window, crossed the old bedroom and laid their eggs on the closet floor. Another man I know keeps his eyes out for roadkill and has a regular vulture feeding station at his rural acreage.
Vultures like to roost overnight out in the open on a dead tree limb or on the ridge of an old barn or corn crib. They often spread their wings to the rising sun to warm up and dry off any dew before soaring away on their daily search for food. They may not fly much at all on cloudy, calm days when they can’t find much rising air. They don’t arrive until April and tend to leave quickly in October when weather begins to cool off. They’re awkward on the ground and decidedly ugly, with their little naked heads and dull, dark feathers. All that changes when they’re effortlessly riding unseen wind currents across a cloud-flecked sky. Few creatures are more graceful. They are truly masters of the summer sky.
(Steve Lekwa is retired director of Story County Conservation. He lives in Nevada.)