The White-tailed Eagle, whose range includes northern Eurasia and Greenland, is a very rare visitor to North America. It resembles a Bald Eagle in plumage, size, and diet. The combined appearance of the head and tail is the most obvious difference in adult plumage between the two species. In the White-tailed Eagle, the tail is the only part of its body that is completely white compared to the all-white head and tail of the Bald Eagle. Immature and sub-adult plumages of the White-tailed Eagles are also similar to those of the Bald Eagle.
The White-tailed Eagle is about the same size as the Bald Eagle in Alaska, making it a large-sized raptor. It is also a superb fisherman, and an accomplished pirate, like the Bald Eagle.
Although quite rare, and in low numbers, the White-tailed Eagle occurs throughout the year in south-western Alaska. There are also several other accidental occurrences for northern parts of the continent.
SIZE
The White-tailed Eagle is a large bird of prey in which the female is larger than the male and averages about 20 percent heavier. Combined, their lengths vary from 27 to 36 inches (69 to 91 centimeters) and average about average 33 inches (84 centimeters). Wingspread measurements vary from 82 to 97 inches (208 to 247 centimeters) with an average of 91 inches (231 centimeters). The weight varies from 6.8 to 15.2 pounds (3.1 to 6.1 kilograms) with an average of 10.6 pounds (4.8 kilograms). The usual weight of a male is about 10 pounds (4.5 kilograms) and a female about 13 pounds (5.9 kilograms).
MORPHS
There are no light or dark color morphs although total albinism has been reported.
SPECIFIC DESCRIPTION
Adult - Flight
- light buffy brown or creamy buff head with yellow bill
- all-brown body with broad wings that appear rectangular
- all-white tail that appears short for the size of the bird and is wedge-shaped
- feathers under the tail are dark
- tips of outer seven primary, or flight feathers, are noticeable. There are six showing in the adult Bald Eagle.
Immature - Flight
- dark head with dark bill
- underparts contrast with a dark brown breast, often with white or light brown streaks, and lighter brown belly without streaks
- pale buff feathers in "armpits" (axillaries)
- individual tail feathers with white spears or spikes
- tail is noticeably longer than the adult's
- tail feathers show dark sides and white inners that together gives a whitish appearance from below
- tips of seven outer primary feathers visible; six in the immature Bald Eagle
SIMILAR SPECIES
The White-tailed Eagle, within its range in Alaska, should only be confused with the Bald Eagle and Steller's Sea-Eagle. The adult Bald Eagle has a pure white head and short fan-shaped tail that is well defined and sharply separated from the dark body. The White-tailed Eagle has a light brown, tan, or creamy buff head and the tail is white but longer and wedge-shaped. Feathers under the tail are white in a Bald Eagle and dark in a White-tailed Eagle. The Steller's Sea-Eagle shows large white wing patches.
Immatures are easily confused as they resemble one another. The tail of immature Bald Eagles have an even and broad dark band near the tip while in the White-tailed Eagle the tail feathers appear spiked. Immature White-tailed Eagles have small whitish armpit areas and few white diagonal lines or white on the wing linings. Seven versus six "fingers" on outer primary feathers of the White-tailed Eagle separates it from a Bald Eagle. Also, the contrast of the breast to belly is less defined in immature White-tailed Eagles. Immature and subadult Steller's Sea-Eagles show mostly white, extremely wedge-shaped tails and very large yellow beaks.
OTHER NAMES
The White-tailed Eagle is also known as the "Cliff Eagle", "Sea-Eagle", "Shore Eagle", "White-tailed Sea Eagle", "Gray Sea Eagle", and "Erne" which is an Anglo-Saxon term meaning "the soarer". The latter name is a favorite selection for crossword puzzles!
ETYMOLOGY
The genus Haliaeetus stems from the Greek word halos meaning "sea", and aetos meaning "eagle". The specific name albicilla is from Latin word albus meaning "white" and illus, a diminutive suffix used mistakenly to mean "tailed". Translated, Haliaeetus albicilla is "White-tailed Sea Eagle."
