Steller's Sea-Eagle

Haliaeetus pelagicus

Steller's Sea-Eagle
© Francesco Veronesi

One of the heaviest raptors in the world, the Steller's sea-eagle can weigh up to 20 pounds. Named after German naturalist Georg Steller, these powerful raptors are amazing, and every birder should learn more about how to protect them.

Common Name: Steller's Sea-Eagle, Steller's Sea Eagle, Pacific Eagle, White-Shouldered Eagle, Mottled Sea Eagle, Great Eagle

Scientific Name: Haliaeetus pelagicus (formerly Aquila pelagic, Faico leucopterus and Thallasoaetus pelagicus)

Appearance

  • Bill: Massive, strongly hooked, bright yellow with yellow cere and gape that also emphasize large size
  • Size: 35-40 inches long with 75-90-inch wingspan, broad bulging wings, large head
  • Colors: White, yellow, black-brown
  • Markings: Genders are similar though females are notably larger with heavier bills. The head is black-brown with white frosting on the crown and nape and a small white patch on the forehead. The yellow eyes are surrounded by a fleshy yellow eye ring. The body is black-brown with a prominent white patch on the shoulders. That white patch is visible both on top and beneath the wings in flight, and in bright light can make the wings look narrow or unbalanced. A dark morph plumage variation lacks the white shoulders. In flight, the wings also show prominent primary feather fingers. The legs are feathered with white bloomers, and the feet are yellow with black talons. The wedge-shaped tail and undertail coverts are plain white.

    Eaglets are covered in white down, but as they mature, juvenile birds develop darker, more uniform brown-black plumage. Juvenile birds show significant mottling in the wings and a thin dark band on the tail tip. Younger birds also have smaller, paler bills. Juvenile birds do not achieve their full adult plumage until they are four years old.

    Foods: Fish, waterfowl, large birds, mammals, carrion (See: Carnivorous)

    Habitat and Migration

    These eagles are believed to be glacial remnants, having evolved during ice age periods and being specially adapted to those extreme conditions. They prefer rocky coastal habitats and are also found inland along large rivers with craggy edges and mature trees.

    In winter, they may also be found near coastal lagoons or in areas where fish are spawning.

    Steller's sea-eagles are year-round residents of much of the Kamchatka peninsula in eastern Russia, as well as along the Russian coast west of the peninsula. During the summer breeding season, they spread out slightly further north along the Pacific coast. In winter, some of these raptors migrate as far south as the Korean coast and along the coast of Hokkaido, Japan. The extent of migration can vary widely depending on food supplies and winter ice coverage.

    Vagrant sightings are rare because these raptors do not move great distances, but they are occasionally recorded as far east as Alaska and as far south as Taiwan.

    Vocalizations

    These eagles are exceptionally vocal for raptors and have a throaty, raspy bark-like call that sounds much like typical gull calls. Their pitch is higher than would be expected for a bird of their size, and they often call while fighting over food or just while flying.

    Behavior

    These raptors use both soaring flight and powered flapping flight, and they can be quite agile in the air. They are diurnal and hunt during the day, either diving from a perch to snatch prey with their powerful talons, or else soaring to find their next meal.

    They may even stand in shallow water and snatch fish with their bills, and they often steal from other eagles or ospreys.

    Steller's sea-eagles are generally solitary and require large territories to support their hunting habits. In winter, however, they will gather in communal roosts near rich food sources, such as fish spawning grounds or rare areas of open water. They may even join mixed flocks with golden eagles and white-tailed eagles while feeding.

    Reproduction

    These are monogamous birds that form pair bonds after soaring courtship flights. Both adults work together to build a huge, bulky nest of branches and twigs, and the same nest may be reused for many years. Some pairs will build multiple nests in close proximity to one another, but only one nest is used for raising chicks. The nests are generally 50-150 feet above the ground, positioned on a rocky outcropping or at the top of a mature tree.

    The eggs are pale greenish-white. There are 1-3 eggs laid in each brood, though it is rare but not unheard of for more than one chick to survive. Incubation lasts 40-45 days, and after the altricial eaglets hatch, both parents continue to care for the young birds for 10-12 weeks until they are able to leave and hunt on their own. Only one brood is raised each year.

    Steller's sea-eagles do not begin breeding until they are at least five years old.

    Attracting Steller's Sea-Eagles

    These large, powerful raptors are not backyard birds, but they will readily visit areas where prey is abundant, particularly salmon and trout. Preserving habitat is essential for attracting these raptors, as well as protecting proven nesting areas.

    Conservation

    Despite their position as powerful apex predators, Steller's sea-eagles are still vulnerable to different threats. Water pollution and overfishing are destroying critical food supplies, while logging operations often remove trees that are needed for nesting or hunting perches. Where these birds feed on carrion, they are subject to lead poisoning. In some areas, they are persecuted by fur trappers because the eagles may occasionally raid traps. Because of these threats, a relatively restricted range, and small population numbers, Steller's sea-eagles are listed as globally vulnerable. Though they are listed as a National Treasure in Japan and are protected under a variety of laws in different countries, strict conservation measures are essential to ensure their survival.

    Similar Birds

    • Bald Eagle (Haliaeetus leucocephalus)
    • White-Tailed Eagle (Haliaeetus albicilla)