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 members of the Accipitridae bird family are amazing, and every birder should learn more about how to protect them. This fact sheet can help!
- Scientific Name: Haliaeetus pelagicus (formerly Aquila pelagic, Faico leucopterus and Thallasoaetus pelagicus)
- Common Name: Steller's Sea-Eagle, Steller's Sea Eagle, Pacific Eagle, White-Shouldered Eagle, Mottled Sea Eagle, Great Eagle
- Lifespan: 20-25 years
- Size: 35-40 inches
- Weight: 11-20 pounds
- Wingspan: 75-90 inches
- Conservation Status: Vulnerable
Steller's Sea-Eagle Identification
This is a massive, heavy raptor, and its massive, heavy bill is strongly hooked and bright yellow. The cere and gape are also bright yellow and emphasize the bill's large size. This distinctive bill is an immediate clue that the bird is an eagle, but birders need to look for other field marks to feel confident about this bird's identification.
Genders are similar though females are notably larger with heavier bills than males. 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, though it can be difficult to see. 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 but shares other traits with the more classically colored birds.
In flight, this eagle's wings 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.
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.
Steller's Sea-Eagle Habitat and Distribution
These eagles are believed to be glacial remnants, having evolved during ice age periods and being specially adapted to those extreme climate 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, these raptors 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, and these birds don't always move far within their range.
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.
These raptors use both soaring flight and powered flapping flight, and they can be quite agile in the air. 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.
Diet and Feeding
Steller's sea-eagles are carnivorous and eat a wide variety of prey, including fish, waterfowl, larger birds, and mammals, and they will also occasionally eat carrion. 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.
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.
Eggs and Young
Steller's sea-eagle 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 baby 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.
Steller's Sea-Eagle Conservation
Despite their position as powerful, top 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.
Tips for Backyard Birders
These large 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.
How to Find This Bird
The easiest way to find these birds is to opt for a dedicated tour that includes birding and wildlife watching. Choose reputable tour operators with experienced guides, and specifically ask about opportunities to see these birds to be sure there are sighting opportunities. Visiting popular fishing areas within the eagles' range is another way to see Steller's sea-eagles.
Explore More Species in This Family
All eagle species are part of the Accipitridae bird family, along with hawks, kites, harriers, goshawks, and buzzards. Great relatives of the Steller's sea-eagle include: