Minnesota Outdoors: Turkey vultures have highly-evolved senses to detect odors

Submitted by Blane Klemek
Crookston Times

    I watched a turkey vulture soar over my property on a beautiful early October morning recently. The bird’s six-foot wingspan, impressive as it is, enabled the vulture to stay aloft without so much as flapping its wings one time. Rocking back and forth as it used its tail and wing feathers to steer through the rising thermals, turkey vultures are efficient in preserving energy as they glide effortlessly through the air in search of food.

    So why do turkey vultures soar in the first place? They mainly do so to find food. Soaring just above the forest canopy or at modest elevations across open landscapes, turkey vultures are relying on their senses as they search the ground below. While turkey vultures do in fact possess keen vision, there’s another sense that this avian scavenger utilizes that is far more important than sight: olfaction—the sense of smell.

    What? Birds can smell things? Most birds have limited senses of smell, but that is not the case for turkey vultures. One look at their beaks will give you a clue as to how advanced olfaction is for turkey vultures. Huge nasal cavities beneath large nasal openings in their beaks, coupled with enormous olfaction bulbs in their brains, combine together to make turkey vultures second to no other bird in their abilities to pick up the faintest odors wafting up from hundreds to thousands of feet below them.  Indeed, you’d be correct in describing a turkey vulture as a bloodhound with wings.

    In an article written by John Barrat for the Smithsonian Insider, Barrat interviewed scientists studying the olfactory bulbs found in turkey vulture brains. Quoted from the article, “Observations of turkey vultures have long shown they have an exquisite sense of smell,” says paper co-author Gary Graves, an ornithologist in the Division of Birds at the Smithsonian’s National Museum of Natural History. “Now, for the first time, anatomical evidence verifies this fact and suggests the turkey vulture may have the most sensitive olfactory senses among living birds—some 11,000 plus species.”

    The olfactory bulb is a sensory organ of the brain that helps control the sense of smell in animals. A highly specialized and sensitive organ, olfactory bulbs (there are two) enables turkey vultures and two other species of vulture to detect the absolute faintest of odors. In fact, the turkey vulture’s olfactory bulbs are up to four times larger than the black vulture’s olfactory bulbs. Black vultures depend on their eyesight to locate food, not their senses of smell like turkey vultures use to locate food.

    Olfactory bulbs are packed with an abundance of special neurons, or cells, that receive important information from smell receptors in a turkey vulture’s nasal cavity. This information is then transferred to the rest of the brain, which enable turkey vultures to discern the scents to identifiable food items from the multitude of different gasses that are released from a decaying carcass.  

    So when you observe a soaring turkey vulture gently swaying to and fro on outstretched wings, what you’re seeing is a bird that is smelling its environment. Riding the air currents, turkey vultures are using their highly evolved senses of smell to detect odors that rise to their nostrils. Once a likely scent has been located, a turkey vulture will circle the area until it’s able to zero in on the carcass, land nearby, and walk to the carcass to feed. Believe it or not, the carcass could be as small as a mouse or vole hidden beneath leaves, grasses, or other debris, which goes to show you just how powerful a turkey vulture’s sense of smell really is.

    Turkey vultures are a truly fascinating and specialized species of bird. Remarkable in flight, unique in habits, and possessing an array of anatomical features that distinguish it from the vast majority of birds, turkey vultures deserve our respect and admiration as a bird worthy of a closer look as we get out and enjoy the great outdoors.