Biology Reference
In-Depth Information
freshest ones. Even though the older carcasses emitted a stronger odor, the vultures
showed a definite preference for eating fresher carcasses.
Greater and Lesser Yellow-headed Vultures of Central and South America, which are
closely related to Turkey Vultures, seem to have comparable reliance on their sense of
smell for finding food, and King Vultures may also use smell to find food. These species
must all be able to find carrion in forests where the canopy visually obscures dead anim-
als.Unlikethesespecies,BlackVultures,whichfindtheirfoodprimarilyinopencountry,
depend far more on vision and are believed to have a relatively poor sense of smell. Of
course, one strategy that all vultures use to locate food is to watch for other circling vul-
tures to drop down suddenly; in that sense, even Turkey Vultures find much of their food
visually.
BAD-TASTING MEDICINE
Some strong tastes elicit
interesting responses in birds. I once watched a fledgling
Blue Jay that I was rehabbing pick up a large ant with the tip of its beak and then open
wide to pull it into its mouth. Suddenly its crest went up and it spit out the insect and
shook its head hard, all the time running its lance-shaped tongue against the roof of its
mouth. Suddenly it picked up the ant again and started smearing the insect against its
feathers.
Many birds engage in “anting.” Ant bodies are covered with a bitter chemical called
formic acid, which may afford birds some protection from mites and lice. One European
researcher studying a population of pipits that were suffering from a heavy infestation
of feather mites learned that mites on birds that had been anting suffered much higher
mortality than the mites on non-anting birds. In the case of my Blue Jay, apparently the
taste of the ant elicited the behavior. People have reported birds anting with other items,
including mothballs, cigarette butts, and onions.
Q How well do birds taste their food?
A
Bird taste buds are similar in structure to mammalian ones, but they have significantly
fewerthanwehave.Chickenshave24tastebudsandpigeonshavefewerthan60,where-
as we humans have about 10,000 and rabbits have about 17,000! Most of our taste buds
are on our tongues, but birds have very few on the tongue, and none at all on the tip. In-
stead, most of their taste buds are on the roof of the mouth and deep in the oral cavity.
One researcher fed bread mixed with quinine to parrots, and they ate it without any
apparent objections. In taste preference tests on pigeons, one researcher found that the
birds rejected sour or bitter solutions, preferred low concentrations of salt and high con-
