The Steller's sea eagle is named after Georg Steller, a German biologist who explored Kamchatka and Alaska in the 1700s. It is the largest of the sea eagles and is called the heaviest known eagle, and it ranks with the harpy eagle and the Philippine eagle among the largest birds of prey.

Sources give the eagle's size in different ways. One source says its body is about 34 to 41 inches (86.5 to 105 centimeters) long. Animal Diversity Web gives the body length of both male and female as 85 to 94 centimeters. A 2009 paper from a Hokkaido wildlife center gives the body length as 89 cm (male) to 100 cm (female), and the wingspan as 210 cm (male) to 230 cm (female). Female Steller's sea eagles are larger than the males. Its wings can stretch up to 8 feet from tip to tip.

Animal Diversity Web gives the average mass of a Steller's sea eagle as 6 kilograms for males and 9 kilograms for females. The 2009 Hokkaido paper gives the mass as 5 to 7.5 kg. Another source says a female can weigh up to about 20 pounds (9 kilograms), and a male weighs less.

A Steller's sea eagle has a dark body with white on its shoulders, thighs and tail. Its very large yellow bill is described as hatchet-like, and it is suited to tough salmon skin. The eagle uses both eyes together, called binocular vision, to judge where its food is. It glides on rising warm air instead of flapping all the time.

The eagle hunts from a perch or while flying, and it catches prey in its talons. Sometimes it stands in shallow water or on ice and grabs fish that swim by. It eats mostly salmon, a kind of fish. Besides fish, it eats crabs, shellfish, small animals, gulls and carrion, which is an animal already dead. It will sometimes steal food from other birds.

Steller's sea eagles nest in eastern Russia, around the Sea of Okhotsk and on the Kamchatka Peninsula, near sea coasts and big rivers. A pair often returns to the same nest each year and adds more branches to it. A female lays one to three eggs in spring. The eggs take about 38 to 45 days to hatch, and a pair usually raises just one chick, even when more than one egg is laid.

A chick is covered in soft gray-white down that slowly changes to brown feathers. It learns to fly when it is about 10 weeks old.

Scientists know little about Steller's sea eagles because their homes in the Russian Far East are remote. In 1997 and 1998 scientists fitted 29 Steller's sea eagle nestlings with satellite transmitters, and 24 of them gave useful data about what they did after leaving the nest.

As of November 2026, estimates put the world's Steller's sea eagles at around 5,000 birds, and several sources say the number is declining. As of November 2026, the IUCN Red List lists the eagle as Vulnerable. Logging that harms their forest habitat is named as a threat. The eagles are protected by law in Russia, Japan, China and South Korea.

In winter, many Steller's sea eagles fly south to Japan, but some stay in Kamchatka and move to open water. Hundreds gather at Kuril Lake in Kamchatka each winter to feed on salmon.

Eagles that migrate by way of Sakhalin Island reach Hokkaido through Cape Soya, the northernmost cape of Japan, in October. The native Ainu people of Hokkaido call the Steller's sea eagle "Kapacchilikamui," which means "God of the Eagles."

Words to know

• wingspan: wing width
• transmitters: signal senders
• binocular: using both eyes
• carrion: dead animal
• Kapacchilikamui: God of Eagles