Bald Eagle Breeding and Nesting
In the Eagle’s Nest from Building to Fledging
The Bald Eagle, Haliaeetus leucocephalus, builds the largest nest of any North American bird. Look for nests where fishing is easy and large trees are available.
When do Bald Eagles Nest?
Bald Eagles don’t usually breed until they are four or five years old. They often mate for life and are typically monogamous.
Nesting takes place at different times in different parts of the continent, depending on weather and the availability of food. In the Southern United States, the breeding season begins in November through January, while eagles in Canada begin nesting in April or May. Many eagles remain in the same geographic area year round; however, those that nest in north and central Canada begin nesting after they have migrated from their warmer southern range.
Nest Location and Construction
Each Bald Eagle pair defends a territory of up to two square kilometers (three quarters of a square mile) around the nest site—this space is needed to provide sufficient food for both adults and growing young. Usually, the nest is located in a forested area near water where there are large trees. Some nests are located surprisingly close to human dwellings.
Eagles build nests in the biggest trees (occasionally on cliff ledges or even on the ground). The sturdy nest is constructed of sticks and twigs, with a lining of fine woody material, feathers, moss, and soft grasses. This species builds the largest nest of any North American bird: a new nest averages up to two metres across (six and a half feet) and one metre tall (about a yard). Because pairs tend to return to the same nest in successive years, or new pairs take it over and add to it, older nests easily reach dimensions of three metres across (almost ten feet) and six metres tall (nearly twenty feet). These large nests can weigh several tons.
Bald Eagle Nesting
The female Bald Eagle usually lays two eggs, occasionally three, and incubates them for about 35 days. Hatchlings, emerging from the egg with a downy covering and open eyes, weigh about 90 gm (about three ounces). Adults feed young scraps of captured prey.
The male does most of the hunting while the female incubates the eggs and cares for hatchlings, protecting them from weather and predators. When the young are about half grown, the female spends longer periods away from the nest, hunting for food.
Juveniles grow quickly—feathers start to grow after four or five weeks, and fledglings begin to fly at about eleven weeks of age.
Interesting Facts About Juvenile Bald Eagles
Young Bald Eagles face many challenges as they mature:
- Typically, only 50% of Bald Eagles survive their first year. Mortality begins in the nest where the larger stronger hatchling gets fed first and may even kill its weaker sibling.
- Because they are not as skilled at hunting, immature Bald Eagles are more likely to steal from other birds and eat carrion. Experienced adults tend to catch their own food.
- Juveniles face starvation if they are not successful at learning to hunt efficiently.
- Juvenile birds travel throughout the continent for four years, covering large distances before they become adult and begin breeding.
Watch a Video of a Bald Eagle Pair in the Nest on Bird Cinema
More About Bald Eagles:
Sources:
“Bald Eagle.” Cornell Lab of Ornithology. All About Birds.
“Bald Eagle: The USA’s National Symbol.” American Eagle Foundation.
“Bird Fact Sheets: Bald Eagle.” Canadian Wildlife Service and Canadian Wildlife Federation. Hinterland Who’s Who.
Birds Of North America. Kaufman, Kenn. New York: Houghton Mifflin; 2000
