Thursday, June 4, 2009

Bird Senses

Nature Watch

By Susan Benson,
CNHM Director of Education

Birds have the same basic five senses we do: sight, hearing, touch, taste, and smell. However, their senses are a bit different because they are custom-tailored for a bird’s way of life. Like people, sight and hearing are the most important senses for birds.

Birds as a group have one of the most highly developed senses of vision in the animal kingdom. The importance of this sense is best illustrated by the larger size of a bird’s eyes relative to other animal groups. For example, heads of both humans and starlings represent about one-tenth of total body weight. The starling’s eye, however, represents fifteen percent of its head weight, compared to less than one percent in humans. An owl, if it could read, could read a newspaper from the other end of a football field. A golden eagle can see a rabbit on the ground from two miles away. Finally, if our vision was the same as birds of prey, our eyes would need to be the size of grapefruits. Now that is amazing eyesight!

The sense of hearing in birds is well developed. The inner ear functions in essentially the same way as a human’s. Songbirds hear in a range of frequencies narrower than those in which a human can hear. If you can’t hear a sound, chances are neither can birds.

For birds, the sense of touch is concentrated primarily in their feet and bill, the areas that are not feathered. Their feet detect feelings of cold, heat and pain. Many birds have a highly developed sense of touch in their bill, which they employ when capturing and manipulating food.

Experiments with birds indicate they have an acute sense of taste, but they have fewer taste buds than mammals. Some birds are insensitive to bitter, sweet, or sour tastes. Aren’t they lucky?

How widespread or important the sense of smell is in birds has been long debated. Research has shown that turkey vultures use smell to locate dead animals to eat. Of all senses, smell is generally the least developed in birds, although their detection and discrimination ability varies considerably among species.
Aesop said, “It is not only fine feathers that make fine birds.” This is certainly true! Next time you see a turkey vulture on its food along the roadsides, just think of the smell they get to enjoy at every meal. Or envy the birds that never have to be tempted by sugar. Whatever they do, birds continue to appeal to our sense of wonder!
Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.

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