From Fuzzy Fluffball to Stately Bird: The Life Cycle of an Eagle

When a much-awaited eagle egg hatches, a tiny cottony ball of fluff slowly emerges. This fuzzy, wobbly handful of cute is utterly dependent on its doting parents. Soon, however, the white fluff gives way to brown feathers and the bird tests its wings, soaring and growing and eventually becoming a regal image of its parents. Here's a look at how tiny eaglets make the remarkable transformation from hairy hatchlings to majestic adult birds.

Hatchlings

It can take as long as a day for the eaglet to completely break free after cracking the egg, a process called pipping. Eggs hatch in the order they were laid, according to the National Eagle Center.

The hatchling emerges completely covered in white fluff and is totally dependent upon its parents for food. It weighs only about three ounces (85 grams). The mother and father take turns caring for the babies. Sometimes both birds are in the nest at the same time. They bring the hatchlings food an average of four times a day.

Nestlings

Before they "fledge" or leave the nest for the first time, young eagles remain as nestlings for about 10 to 12 weeks. That's how long it takes them to develop enough feathers to fly and grow large enough that they can start hunting on their own.

As they get older, they practice flapping their wings. Brown feathers appear when the birds are about 5 weeks old. By this point, the white fluff is gone. They are nearly full feathered by the time they are about 9 weeks old.

The parents will continue to tear food and feed it to the chicks until they can feed themselves. Nestlings typically can start to feed themselves beginning when they are around 40 days old, according to the Center for Conservation Biology.

As the nestlings get closer to fledgling stage, the adults may withhold food to encourage them to leave the nest in order to find a meal.

"Usually, no coaxing is necessary and the eaglets are all too anxious to test their wings!" says Peter E. Nye, New York State Dept. Environmental Conservation, Division of Fish, Wildlife and Marine Resources.

Fledglings

According to the National Eagle Center, young bald eagles are generally ready to fledge, or take their first flight, by 10 to 12 weeks of age. Young golden eagles typically fledge when they're around 10 weeks old. They start by soaring to a nearby tree, then gradually increase their distance as they get more confident with their flying abilities.

Fledglings continue to return to the nest and stay near their parents for a month or more, learning how to hunt and hone their flying abilities. They may continue to get food from their parents, as long as the adults are willing to feed them.

How long eagles stay with their parents after fledging depends on how independent they feel, says Nye.

"Some youngsters 'bust-out' quickly, thinking they are fully capable of being on their own," he says. "In many cases, they pay for this with their lives during their first fall and winter. On average, I'd say they spend 4-12 weeks in the nesting territory post-fledging, the time during which they learn to hunt and fly."

Juveniles

Sometimes also called a sub-adult, a juvenile is typically an eagle in its first year that doesn't yet have full adult plumage.

According to the National Eagle Center, juvenile bald eagles can appear larger than their parents in the first year because of longer flight feathers that help the birds as they learn to fly. After the first molt, the wing feathers will be the same size as an adult’s.

Juveniles have a brown body with brown and white mottled wings. The tail is also mottled with a dark band at the very tip, according to the Cornell Lab of Ornithology.

Adults

With each molt, eagles grow closer to the classic adult plumage. Most birds have the white head and tail feathers between their fourth and fifth year, although some never entirely lose the brown pattern. That's typically a sign the birds have reached sexual maturity and begin breeding.