Why the mighty sea eagle is often nicknamed the flying barn door

Nature · Published 3 October 2026 Swipe more like this →

In short: The white-tailed eagle is the UK’s largest bird of prey, boasting a massive wingspan and a distinctive, wedge-shaped tail. Known for their opportunistic hunting and scavenging, these birds were once driven to extinction in the UK by human persecution, only to make a triumphant return through dedicated reintroduction projects.

Sea eagles, belonging to the genus Haliaeetus, are large, fish-eating raptors found across the globe, excluding South America. The white-tailed eagle, the largest in Europe, is a prime example of this group. These birds are easily identified by their broad, rectangular wings—earning them the affectionate nickname 'flying barn door'—and their striking white tail feathers as adults. They are versatile hunters, plunging into water to snatch fish or scavenging carrion, especially during the colder winter months when activity levels drop and their daily food requirement falls to 200-300 grams.

The history of these birds is marked by intense human conflict. In the UK, the white-tailed eagle was driven to extinction by the early 20th century due to illegal killing, with the last known individual in Scotland shot in 1918. Similarly, in the United States, the bald eagle—a fellow member of the sea eagle group—faced severe population declines. Between 1917 and 1952, bounty hunters in Alaska killed over 100,000 eagles, viewing them as a threat to salmon fishing. By the 1960s, the species was further decimated by the pesticide DDT, which caused eggshells to thin and break, leaving fewer than 450 nesting pairs in the lower 48 states.

Conservation efforts have been instrumental in their recovery. Following the 1972 ban on DDT in the U.S., bald eagle populations rebounded, leading to their removal from the endangered species list by 2007. In the UK, the RSPB and Scottish Natural Heritage led successful reintroduction projects starting in 1975, with further releases occurring as recently as 2019 on the Isle of Wight. Despite these successes, the UK population remains small, with estimates suggesting fewer than 150 pairs. These birds remain highly sensitive to their environment, as seen in their tendency to accumulate chemicals like PCBs and DDT from their prey, such as fulmars, which can impact their reproductive success.

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