Repulsive but useful vulture

The other day I was walking along the edge of Pierce Lake in Rock Cut State Park and noticed four large birds making lazy circles in the air. I used my binoculars to identify them immediately as turkey vultures.

Distance certainly lends itself to the enchantment of the turkey vulture, as it is much more attractive when high in the ozone and sailing gracefully in ever-changing circles without apparent effort. Closer inspection of a turkey vulture, however, reveals what many consider to be a repulsive and hideous creature.

Persnickety people tend to look down their noses at this bird because of the wrinkled, red, bare skin covering its grotesquely-shaped head and because of its diet of carrion, garbage, and other such tidbits. However, we should not indulge in anthropomorphism (judging animals by human standards), as I am sure turkey vultures are considered to be beautiful and delightful creatures by other turkey vultures.

This outcast of the bird world is an unpaid and willing sanitation worker and is quite valuable in maintaining the overall health of the environment. In fact, it is in such good standing as a “feathered street cleaner” that it is a protected species in many parts of the country. If there is a dead horse or cow in a field, a deer killed by a car along the roadside, or a dead fox in the woods, vultures will find it and quickly gather to dispose efficiently of the remains. When they happen on such a bonanza, they will not leave until all but the bones have been consumed. If the carcass happens to be a large one, they will often remain near their food supply for days, roosting at night in nearby trees.

After they have filled their stomachs to repletion, sometimes stuffing themselves until food will be forced out of their mouths when they move, they will, if not too heavy to fly, retire to a secluded area until the meal is partially digested.

As soon as more space is made available in the stomach by digestion, they will return to the banquet table for more. Regurgitation is practiced frequently, and the forced, partially digested food can be expelled for some distance to protect themselves from potential enemies. This terrible table manner, which puts another black mark on their reputation, may seem quite offensive to us but is welcomed by the young who are fed in this manner.

Inexperienced bird watchers may sometimes confuse a high-soaring vulture with a golden eagle or an immature bald eagle before it has developed its characteristic white head and tail. The best way to avoid this mistake is to remember eagles are uniformly dark on the undersides of their wings, and there is a two-tone pattern to the undersides of the vulture’s wings that is visible as they soar overhead. The forward halves of the vulture’s under wing are the same blackish color as the rest of the body, but the rear halves are a brownish color that stands out in contrast.

A close relative of the turkey vulture is the somewhat smaller black vulture that does not range as widely as its cousin. It keeps mainly to the southeastern and south central parts of the U.S., but we may occasionally see one here in northern Illinois. The bare skin of the black vulture’s upper neck and head is not red, but a dirty pearl-gray, or even darker color.

Years ago, a professor in a vertebrate zoology class of which I was a member stated that Charles Darwin was very interested in how vultures located their food supply. At the time, some said it was by smell and others claimed it was by sight, but Darwin determined that vultures located their dead animal meal totally by sight, and smell had nothing to do with the process.

The professor went on to say that he agreed with Darwin in this matter as he had once conducted an experiment to test the sight hypothesis. He described how, in a field on a hot August day in rural Mississippi, he had lain motionless for a period of 20 minutes and had attracted a large number of vultures that circled overhead sizing up the possibility of a meal. A student in the back of the lecture hall, who was known as a smart aleck, immediately interrupted by shouting, “Hell, prof, your experiment didn’t prove anything.”

Dr. Robert Hedeen is a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960 to 1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.

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