Journey North Bald Eagles

Bald Eagle

How Eagles Fly

To learn the general principles of bird flight, you might want to start with our Bird Flight Primer.

Eagles have very long, large wings, a short neck, and legs short enough to tuck into their belly feathers while aloft, except when they're fishing. Their wings are long and wide enough to carry their own body weight plus the weight of most of the fish that they carry.

It takes a lot of energy to flap such large wings, just like it's a lot of work running with a large kite until it takes off! Two scientists who studied eagles, Jon. M. Gerrard and Gary R. Bortolotti, write that "Eagles are capable of sustained flapping flight but they usually spend little time doing it. During the month when Cindy (one of the female eagles they studied) was observed intensively, she averaged less than 2 minutes per hour in flapping flight. That is not surprising when one considers the large expenditure of energy required by the pectoral and supracoracoid muscles to power the huge wings. The energy needed to maintain a bird in flat soaring or gliding flight is much less, perhaps a 20th or less the power needed for flapping. Therefore, eagles will always choose to soar or glide when possible."

This silhouette was drawn from a real eagle. But can it fly?

That is why when eagles are flying long distances, especially on migration, they often soar on thermals until they reach a great altitude, and then use the gliding/soaring method of flying to cover the longest distance using the smallest amount of energy.

Try This!
See if you can design an eagle that can really fly, or at least glide. Use cardboard, paper, paste or glue, paper clips, and any other materials you want to try. If you want a pattern designed from a real eagle silhouette, click on the small pattern to see a larger sized one. Or try to develop your own pattern, from paper airplane designs or anything else that might work. Classes can test the birds to see which stay aloft the longest, and which fly the farthest.