April

Hatching/Rearing
Taking Care of Nestlings:
8 - 14 weeks

The first egg to be laid is the first egg to hatch. It can take a whole day for the baby to work its way out of the egg--the parents probably don't help the babies get out. And once the babies hatch, the parents don't get rid of the shells. The broken shells sit at the bottom of the nest sometimes for a long time before getting crushed so small that they aren't noticeable anymore.

Some scientists did a study keeping track of all the time that the parent eagles spent at the nest. Once the babies hatched, the female was present at the nest about 90% of the time. The male was present about 50% of the time. This adds up to more than 100% because sometimes BOTH parents are present at the nest. During the study, at least one of the parents was at the nest almost all the time.

When the weather is hot and sunny, one or both of the parents shade the babies. During the first four weeks after hatching, one of the parents (usually the female) broods the babies to keep them warm almost all the time, especially when the weather is cool. At this time, females brood about 65% of the time and males about 35%.

In one study, the parents brought food to the nest 1 - 8 times per day. The average was about 4 times a day. During the first two weeks, the male provides most of the food. After 3 or 4 weeks, the female provides as much food as the male, and by the late nesting period, the female provides most of the food.

As the babies eat, poop, and grow, the nest starts getting dirty. The babies usually lean over the edge of the nest to poop, but once in a while they miss! And food particles remain in the nest after each feeding. After a while, these build up to a goopy, stinky mess. Eagles simply do not have any idea about cleaning their nest. Instead, they add fresh leaves and other plant parts to cover up the mess. (This is a lot like sweeping dirt under the rug or hiding dirty clothes under your bed!)

The young practice flapping for weeks before their first flight. Sometimes one of them falls from the nest. If this happens, it can't usually get back into the nest. But the parents usually feed it on the ground. Sometimes when the babies remain in the nest for 11 or 12 weeks, the parents seem to encourage the babies to fledge by flying around the nest carrying food.

Caption Page: Feeding the Young
During the nesting season, adults carry prey to the nest to feed the young. Adults feed their chicks by tearing off pieces of food and holding them to the beaks of the eaglets. After fledging, immature eagles are slow to develop hunting skills, and must learn to locate reliable food sources and master feeding techniques. Young eagles will congregate together, often feeding upon easily acquired food such as carrion and fish found in abundance at the mouths of streams and shallow bays and at landfills.

Caption Page: Growing and Changing
Development of Bald Eagle Young

Week One: At hatching, the young are covered with a light gray down and have limited mobility. Their eyes, dark brown in color, are closed, but open after a few hours. The female parent does the majority of the brooding while the male parent provides most of the food for the family. Aggressive antagonistic behavior can appear shortly after hatching wherein the oldest, largest eaglet tries to dominate or even kill its sibling(s).

Week Two: The second down plumage, darker in color, begins to replace the first. At the end of this period thermoregulation is attained; that is, the eaglet can maintain its own body temperature under normal weather conditions without brooding from an adult.

Week Three: Black contour feathers on back, shoulder, breast and wings begin to emerge.

Week Four: Flight feather development underway.

Week Five: Male and female parents bring relatively equal amounts of food. Parents begin spending more time away from the young and often perch in nearby trees.

Week Six: Young are able to tear pieces of food off and feed themselves, and begin to stand and walk.

Week Seven: Maximum body growth nearing completion.

Weeks Eight - Twelve: Nestlings begin "branching". They flap their wings while perched on the nest and hop onto nearby branches, practicing and building up flight muscles, coordination, and landing skills. Most of Oklahoma's Bald Eagles fledge between 11 and 12 weeks after hatching. After the first flight the eaglets may return to the nest a few times to spend the night (roosting) or to get food brought there by the adults.

After fledging the young are still dependent on the adults to feed them for a period of up to a couple of months until they gain the experience and skills to find and catch their own food. Radio-telemetry studies of a few Bald Eagles reared in Oklahoma show that they migrate north during the hottest months of the summer to cooler climates such as the Great Lakes area or Canada.

Facts and Photos

• Nesting Timeline