Eagle wings and feathers work together to make a perfect lightweight team. The feathers of a Bald Eagle have many functions, including keeping it warm. The feathers are perhaps the most important component of flight. An adult Bald Eagle has over 7000 feathers, but if you put all of them together they would weigh less than 21 ounces, or 30 feathers would weigh less then a penny. Not only are the feathers incredibly light, but they are also strong.
| If you put a feather under a microscope, you would see that each strand of the feather is held together by tiny hooks. These hooks are called hook barbules; the part that they hook onto are called bow barbules. All feathers are made up of a substance called keratin. Keratin is the same substance that make up our fingernails. The way the feathers attach to the wing is also important in keeping the eagle light. The feathers overlap each other, which creates lots of air pockets between the feathers. |  |
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An eagle's feathers are divided up into different groups. Each group has its own special job that helps the eagle fly and soar. On the wing there are three types of feathers; primary feathers, secondary feathers, and covert feathers. Covert feathers add thickness to the front of the wing so air moves faster over the top of the wing. Primary feathers can be spread out like fingers on a hand to reduce drag. Secondary feathers move up or down to control the amount of drag. |
| The eagle's wings are very large and powerful, yet do not weigh it down. A female Bald Eagle can have wings that are eight feet in length, but weigh less than two pounds. The shape of the wing is long and wide, which allows the eagle to soar and glide. Broad wings allow the eagle to stay up in the air longer without pumping its wings. The shape of the wing also gives the eagle greater strength when it lifts its prey. Pound for pound, an eagle's wing is stronger than the wing of a jet plane. |  |
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Original: January 1998
Updated: 10-Sept-99
Comments: bradwood@indiana.edu