The insecticide DDT got into fish, and eagles that ate them laid eggs with shells too thin to last; DDT dissolves in fat and builds up as it passes up the food chain, which put top predators such as bald eagles at great risk. In 1963 only 417 nesting pairs of bald eagles were known in the lower 48 states. The United States banned DDT for most uses in 1972. In 2007 the U.S. Fish and Wildlife Service estimated at least 9,789 nesting pairs in the contiguous United States, and by 2009 the lower 48 states had an estimated 72,434 bald eagles, including 30,548 breeding pairs. As of November 2026, estimates from 2018 to 2019 put the lower 48 states at 316,700 bald eagles, including 71,467 breeding pairs. Washington State's bald eagles grew by about 700 percent from 1981 to 2005, about 9 percent a year.

Eagle nests are usually in tall trees, but they have also been found on cliffs, on the ground and on towers and power poles, and in the tallest trees a nest can be built 180 feet or more above the ground. In treeless places such as Alaska, bald eagles nest on the ground, often on cliffs, sea stacks or ridges that are easy to fly to. Nesting starts at different times in different places: September in Florida, February in Ohio and January in Alaska. Tree nests are most often 1.5 to 2 meters across and 0.7 to 1.2 meters tall, and a pair sometimes finishes one in 4 days, though it can take 3 months. A pair comes back to the same nest year after year, and eagles nesting in Alaska reuse a nest for 13 years on average, but nests in southern Florida and Saskatchewan are used for about 5 years.

A pair most often lays two eggs, and sometimes one or three, about 36 hours apart, which raises the chance that at least one egg hatches when conditions are best. Both parents take turns keeping the eggs warm, and mothers sit on the eggs about 3 to 7 times more often than fathers do. The eggs hatch after about 35 days, and a newborn bald eagle weighs about 60 grams and may gain up to 180 grams a day. The nestlings are fed 4 to 5 times a day, and young eagles stay in the nest for 10 to 12 weeks.

Eagle fledglings leave the area at around 17 to 23 weeks and explore for 4 to 5 years as they grow from juveniles to adults. A Florida study found that a year after leaving the nest, 89 percent of young eagles in rural places and 65 to 72 percent in suburbs were alive, and as of November 2026, recent studies show that about 70 percent of eaglets survive their first year. Young bald eagles are mostly brown, and they get a white head and tail when they are about four or five years old. Bald eagles usually first breed at about 5 to 6 years old, and adults may skip laying eggs in some years. As of November 2026, in the wild, bald eagles in Yellowstone are expected to live about 15.4 years and those in Prince William Sound about 19 years. The oldest known wild eagle, in Alaska, lived 28 years.

Bald eagles are found throughout North America, and bald eagles that nest in the north generally fly south in winter, to open water. Southern adults that breed south of 40 degrees north are often permanent residents, while northern interior birds migrate south between August and January. Birds from the upper Midwest may travel 6 to 151 days to reach their summer range and 15 to 77 days to reach their winter range. In winter many bald eagles gather near rivers where salmon come to spawn, and when they are not nesting, they often rest together at shared roosts. Eagles pick roost trees for their height, their width and the shelter they give from bad weather, usually within a kilometer of water.

A hungry bald eagle waits on a favorite perch until it sees a fish near the surface of the water, and it also hunts by flying low over water or land. Bald eagles have large, forward-facing eyes and probably see well with both eyes together, and a bald eagle sees at least four times better than a person. Its eyes cannot move from side to side, so it turns its whole head to look around, and it has little sense of smell. A bald eagle is reported to dive at speeds up to about 100 miles per hour, and it takes fish from near the surface and does not dive under the water.

An eagle grabs its prey with the sharp talons on its toes, and the tendons and tendon sheaths in its legs ratchet its toes shut, so it can hold on for a long time without tiring the muscles. Its grip is about 10 times as strong as a person's, and it can carry prey up to about half its own body weight. Fish is its favorite food, and it also eats ducks and small animals such as rabbits. A bald eagle can go several days without food, and it eats a lot when food is found, storing it in its crop.

Bald eagles need three things: enough food, nest sites close to the food, and reasonable freedom from disturbance while nesting; bald eagles live near water. In Oregon and Washington, bald eagle home ranges were 6 to 47 square kilometers, averaging 22. A river's flow speed and rain can affect how well an eagle catches fish, and bald eagles forage much less when people are active nearby, so their feeding may drop by as much as 35 percent.

Words to know

• insecticide: bug poison
• contiguous: touching, joined
• fledglings: young flyers
• roosts: resting places
• crop: a food pouch