Wednesday, January 18, 2012
Eagles build large nests, called aeries, out of sticks and twigs. They line the aerie with bits of fur from their prey. I don't imagine that the aerie smells very good to humans, but it is a soft place for eggs, and later, eaglets. When the eaglets are big enough to start moving around, the mother eagle strips the fur out of about half of the aerie, exposing the hard, scratchy sticks. There isn't enough room for all the eaglets to sit on the remaining fur lining, so they constantly jostle each other around, looking for a comfortable place. This movement helps them strengthen their leg and wing muscles. The mother eagle stands over her eaglets, flapping her wings so that the eaglets will imitate her. Eventually, the eaglets discover that they can crawl onto their mother's back, and this is a nice soft place for them. The mother allows this, and she lets her eaglets get accustomed to sitting on her back.
When she decides that the eaglets are ready, the mother flies out of the aerie with an eaglet on her back. She carries each eaglet aloft in turn, letting them experience the freedom of flight, while keeping them safe on her back. After they become accustomed to these rides, the mother eagle steps up her game. She carries an eaglet out of the nest on her back, as usual, but then she tilts her wings, allowing the eaglet to slip off her back and go into free fall. The eaglet begins to flap its wings, like it did in the nest, but the flapping is frantic and uncoordinated. The mother lets her eaglet fall a short distance, flapping madly but not very effectively, then she swoops underneath and catches the eaglet. She brings it back to the nest and takes the next eaglet out for its first solo "flight". Something in the instinct of eagles tells them that, even though they just saw what their mother did to their terrified siblings, they should trust their mother not to let them come to any harm.
After a few of these free falls, the eaglets begin to learn to use their wings, and they stay aloft a little while before the mother catches them. They learn to maneuver and to find the updrafts that carry them aloft. Eventually, they can control their flight well enough swoop down and capture small animals and carry them back to the nest.
The day comes when each young eagle flies away from the nest, never to return. The day has come for the young eagles to build their own aeries, and the cycle begins again. Each of these eagles has reached a point where they say (in their own way) "Thanks, Mom. I think I can handle this on my own now."