Bald Eagle

Identification

A massive sea eagle, 70–102 cm long with a span up to 244 cm, and one of the few raptors whose adult plumage needs no study to name: snow-white head and tail, dark brown body, and a heavy yellow bill that curves into a deep hook. The white head is not reached until roughly four to five years of age. Younger birds are a mottled patchwork of brown and white with a dark bill, and a four-year-old with a mostly white head and still-dark tail tips is a classic source of confusion.

Fish makes up the bulk of the diet, taken by snatching prey from the surface rather than plunging. The bird also hunts waterbirds, scavenges carcasses, and routinely robs Ospreys of their catch in midair — a behaviour that has caused more than one lakeside observer to misread what they were watching. Nests are enormous stick platforms in tall trees near water, added to year after year until they can weigh more than a tonne and rank among the largest nests built by any bird. The voice is startlingly thin for the bird's size: a weak, high chattering whistle, which is exactly why films usually substitute a Red-tailed Hawk's scream.

Winter is the best window in most of its range, when birds gather at open water along rivers and reservoirs, often dozens to a stretch of unfrozen current. Look for the flat, plank-like wings in a shallow glide and the laboured, unhurried wingbeats, and check every distant bird carefully for the brown head of an immature.