Bald Eagle (Haliaeetus leucocephalus)
The Bald Eagle is a large raptor or bird of prey found in North America. ). Its range includes most of Canada and Alaska, all of the contiguous United States, and northern Mexico. It is found near large bodies of open water with an abundant food supply and old-growth trees for nesting.
The plumage of an adult Bald Eagle is evenly dark brown with a white head and tail. The tail is moderately long and slightly wedge-shaped. Males and females are identical in plumage coloration, but sexual dimorphism (physical differences) is evident in the species in that females are 25% larger than males. The beak, feet and irides are bright yellow. The legs are feather-free, and the toes are short and powerful with large talons. The highly developed talon of the hind toe is used to pierce the vital areas of prey while it is held immobile by the front toes. The beak is large and hooked, with a yellow cere (a waxy, fleshy covering at the base of the upper beak). The adult Bald Eagle is unmistakable in its native range.
The plumage of the immature is a dark brown overlaid with messy white streaking until the fifth year, when it reaches sexual maturity. mmature Bald Eagles are distinguishable from the Golden Eagle (Aquila chrysaetos), the only other very large, non-vulturine bird in North America, in that the former has a larger, more protruding head with a larger beak, straighter edged wings which are held flat (not slightly raised) and with a stiffer wing beat and feathers which do not completely cover the legs.
The Bald Eagle has a body length of 70–102 cm (28–40 in). Typical wingspan is between 1.8 and 2.3 m (5.9 and 7.5 ft) and mass is normally between 3 and 6.3 kg (6.6 and 14 lb). Females are about 25% larger than males, averaging 5.6 kg (12 lb), and against the males’ average weight of 4.1 kg (9.0 lb). The largest eagles are from Alaska, where large females may weigh up to 7.5 kg (17 lb) and span 2.44 m (8.0 ft) across the wings.
Bald Eagles build some of the largest of all bird nests—typically 5 to 6 feet in diameter and 2 to 4 feet tall, and ranging in shape from cylindrical to conical to flat, depending on the supporting tree. Both sexes bring materials to the nest, but the female does most of the placement. They weave together sticks and fill in the cracks with softer material such as grass, moss, or cornstalks. The inside of the nest is lined first with lichen or other fine woody material, then with downy feathers and sometimes sprigs of greenery. Ground nests are built of whatever’s available, such as kelp and driftwood near coastal shorelines. Nests can take up to three months to build, and may be reused (and added to) year after year.
Bald Eagles nest in trees except in regions where only cliff faces or ground sites are available. They tend to use tall, sturdy conifers that protrude above the forest canopy, providing easy flight access and good visibility. In southern parts of their range, Bald Eagles may nest in deciduous trees, mangroves, and cactus. It’s unknown whether the male or the female takes the lead in selecting a nest site. Nests are typically built near the trunk, high up in the tree but below the crown (unlike Osprey nests).
References: Wikipedia, Cornell Lab of Ornithology