Acute Sense of Smell

Turkey vultures (Cathartes aura) are often seen gliding or soaring in the air or devouring carrion in farm fields, pastures, meadows and along roads. Rarely do they come into yards or around houses unless there is something dead nearby. Turkey vultures are common in our area but we never see them close to our house. When several turkey vultures were sitting above our house (Modoc County  CA) in the cottonwood tree branches, Leonard and I wondered why they were there and speculated that there must be something dead in the area. Unfortunately we discovered one of the two fawns who, with their mother, enjoyed nibbling the shrubbery in our yard dead on the road in front of the house. The turkey vultures were using the cottonwoods as a perch while eating the dead fawn. They remained in our trees for two days until the carrion was gone.

The diet of a turkey vulture is mainly carrion. They rarely attack living prey. Turkey vultures have an acute sense of smell and can detect odors in the air at a concentration of a few parts per billion. Although most birds have a olfactory system that is primitive or small and do not use the sense of smell for food location, turkey vultures have the largest olfactory system of all birds and smell is a primary means of obtaining food. They can smell carrion over a mile away and can detect carrion 12 to 24 hours old by smell. Turkey vultures prefer fresh meat whenever it is available and will, if possible, avoid overly putrid meat.

Turkey vultures glide in the air column until they locate a plume of odor from decaying carrion. By flying in circles, the turkey vulture homes in on the densest part of the olfactory gradient which it then follows to the source. Ethyl mercaptan, a sulfur smelling component of carrion odors, is added to natural gas as an aid in detecting leaks of this flammable gas. Turkey vultures will often congregate around natural gas pipeline leaks, drawn by the smell of ethyl mercaptan.

The genus name, Cathartes, is a Latinized form of the Greek “katharsis”, meaning purify or cleansing. “Aura”, the species, comes either from the Latin “aureus” (golden) or the Greek “aura” (breeze). Whichever the correct derivation of the scientific name, “golden purifier” or “cleansing breeze”, the turkey vulture’s role in removing carrion is described by the name.

Previous posts about turkey vultures include “Turkey Vulture” on 12-19-11, “Only a Mother” on 02-25-12. . .    and “Spread Wings” on 02-29-12.

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