Steller’s sea eagles are large diurnal birds of prey that primarily feed on fish, particularly salmon and trout. They are solitary birds, spending much of their time soaring or perched on sea cliffs or trees looking for prey. During the breeding season, Steller’s sea eagles are monogamous and form long-lasting pair bonds, nesting on large rocky outcroppings or at the tops of large trees on the coast and alongside large rivers with mature trees.

Steller’s Sea Eagles’ Unique Sleeping Behavior

Steller’s sea eagles have a unique way of conserving heat during the winter months. They turn their head under their scapular feathers while they sleep, reducing heat loss across their unfeathered legs. This behavior is not limited to Steller’s sea eagles, as other birds, like members of the grouse family, also sleep on the ground, arranging themselves in tight circles with their heads facing outward.

Sleeping on the Pack Ice

Image source: stellers sea eagle

Interestingly, Steller’s sea eagles are known to sleep on the pack ice off the coast of Hokkaido, Japan, using it as a fishing platform and sleeping on it overnight. During blizzards, the pack ice sinks below the surface of the Pacific Ocean, and fully resurfaces about half a day after a storm. During these storms, one hundred percent of boats stay on shore, and most raptors take shelter on the mainland or on Russian-held islands. But once the weather clears, the raptors return to the pack ice to fish and sleep overnight.

Territorial Behavior

In terms of territorial behavior, Steller’s sea eagles and their Hokkaido endemic cousins, the White-tailed Eagles, warn potential intruders that they are venturing too close to their domain by vocalizing in a higher or sharper pitch and posturing or fluffing up their feathers.

Sleeping Habits of Other Aquatic Birds

Aquatic birds, like the Common Eider, which is abundant along the Maine coast in the winter, snooze while floating on the water, using their down feathers to keep warm. Some birds, like swifts and albatrosses, are able to sleep while on the wing, spending months in the air without landing.

Comparison with Other Raptor Species

Unlike some raptor species that sleep on the ground or in trees, Steller’s sea eagles have a unique sleeping behavior of turning their head under their scapular feathers to conserve heat. This adaptation allows them to thrive in the harsh winter conditions of their coastal habitats.

Conclusion

In summary, Steller’s sea eagles have a unique way of sleeping, conserving heat, and warning potential intruders. They are solitary birds that primarily feed on fish, and they nest on large rocky outcroppings or at the tops of large trees on the coast and alongside large rivers with mature trees. During the winter, they sleep on the pack ice off the coast of Hokkaido, Japan, using it as a fishing platform and sleeping on it overnight.

References:
– Animalia.bio – Steller’s Sea Eagle
– Colby College – Maine Birds
– Japan Dream Scapes – Hokkaido Birding Photo Tour