Haliaeetus pelagicus

Geographic Range

Steller's sea eagles are native to eastern Russia, specifically, the Sea of Okhotsk and the Kamchatka Peninsula. They are frequent winter migrants south to the Japanese Islands of Kuril and Hokkaido and have been seen as far south as eastern China and Korea. Vagrant individuals have also been spotted in Taiwan and the United States.

• Biogeographic Regions
• palearctic palearctic
  • native native

Habitat

Steller's sea eagles breed along sea coasts or near large rivers with mature trees. Sightings very far inland are rare, as they prefer sea coasts that are dotted with estuaries and river mouths. They nest on large, rocky outcroppings or at the tops of large trees. Steller's sea eagles are generally found at elevations ranging from sea level to approximately 100 m.

Migrating Steller's sea eagles winter along rivers in Japan and occasionally move to mountainous inland areas as opposed to the sea coast. They are also occasionally seen over and perching on sea ice in northern waters.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• saltwater or marine saltwater or marine
• freshwater freshwater

• Aquatic Biomes
• rivers and streams
• coastal coastal

• Wetlands
• marsh marsh
• swamp swamp

• Other Habitat Features
• riparian riparian
• estuarine estuarine

Physical Description

Steller's sea eagles are large eagles with dark brown to black feathers on the majority of the body and white on the shoulders, thighs, and crown. They have wedged-shaped, white tails, very large yellow beaks, and sharp, yellow talons. Average mass is 6 kilograms in males and 9 kilograms in females. Body length of both males and females ranges between 85 and 94 centimeters with average wingspans of females around 136 centimeters and males around 118 centimeters.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Steller's sea eagles are monogamous, they are often seen in breeding pairs throughout the breeding season, usually lasting from February through August. Both males and females secure their own breeding territories early in the season and nest building occurs in February or March. Displaying begins in March and consists of soaring high above the breeding area while calling.

• Mating System
• monogamous monogamous

Both male and female Steller's sea eagles reach sexual maturity by six or seven years. Breeding occurs seasonally between February and August, beginning with nest building in February and March. Typically, a pair will maintain two to four nests in one breeding territory and use alternate nests from year to year. Nests are most often built on rocky cliffs or in large trees out of thick branches and can reach a size of two meters across and two to four meters thick. The average clutch size is 2 but ranges from 1 to 3. The egg-laying period normally lasts from April through May, and the typical incubation period is 38 days. Eggs hatch between May and June, with fledging taking around 70 days. Chicks leave nests by August or September.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

At this time, little is known about the parental investment of Steller's sea eagles. Both parents contribute to raising offspring to independence.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

Little is known about the lifespan of Steller's sea eagles, but it is thought to be similar to that of their close relatives, white-tailed sea eagles ( Haliaeetus albicilla ), which live 20 to 25 years in the wild.

Behavior

Steller's sea eagles are solitary birds, congregating with others only to breed. However, large numbers can be seen congregating on particularly productive salmon rivers due to an abundant food supply. Steller's sea eagles are commonly seen perching on cliffs above the sea or in large trees. They are active during the day and migrate to warmer areas in the winter.

• Key Behaviors
• flies
• motile motile
• migratory migratory
• solitary solitary

Home Range

Home range sizes of Steller's sea eagles are not known, but productive nests have been reported to be as close as within 100 meters.

Communication and Perception

Steller's sea eagles communicate mainly through various vocalizations. A deep, barking cry is commonly heard. During mating displays a loud, gull-like call is used.

• Communication Channels
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

The main prey of Steller's sea eagles are salmon , taken either dead or alive. When salmon is scarce or not available, other food resources are taken, ranging from invertebrates like crabs and mussels to gulls, small mammals, and carrion. Three types of hunting behaviors have been observed, hunting from a perch, hunting on the wing while circling 6 to 7 meters above the water, and hunting in shallow water. Kleptoparasitism has also been observed when feeding occurs in groups and food is abundant, adults benefit the most from this behavior.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • scavenger scavenger

• Animal Foods
• birds
• mammals
• fish
• carrion carrion
• mollusks
• aquatic crustaceans

Predation

There are no known predators of adult Steller's sea eagles. Eggs and hatchlings are commonly preyed on by arboreal mammals that gain access to nests, such as martens, and by crows.

Ecosystem Roles

Steller's sea eagles are important predators of salmon and other prey in their native ecosystems.

Economic Importance for Humans: Positive

There are no described benefits of Steller's sea eagles to humans.

Economic Importance for Humans: Negative

Steller's sea eagles have been known to remove mammals from commercial traps set by humans during harsh winters, causing some harm to that industry.

Conservation Status

Steller's sea eagles have a limited population size of around 5,000 individuals. Populations are in steady decline. Potential causes of declining populations are habitat degradation due to an increase in industry and logging, overfishing of key prey items, and pollution.

Steller's sea eagles are listed as vulnerable on the IUCN Red List of Threatened Species because of their small and declining population sizes. Steller's sea eagles are legally protected in Russia, Japan, China, and South Korea with key habitat areas being established as nature reserves throughout Russia and Japan. They are also protected under Appendix II of the Convention on International Trade of Endangered Species.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Danielle Nelson (author), Northern Michigan University, Alec R. Lindsay (editor, instructor), Northern Michigan University.

References

Brown, L., D. Amadon. 1989. Eagles, Hawks and Falcons of the World . Edison, New Jersey: The Wellfleet Press.

Collar, N. 2001. Threatened Birds of Asia: The BirdLife International Red Data Book . Cambridge, UK: Birdlife International.

2007. "BirdLife International Species factsheet: Haliaeetus pelagicus" (On-line). Accessed March 17, 2008 at http://www.birdlife.org .

1999. "Species Synopsis Stellar Sea Eagle" (On-line). Accessed March 24, 2008 at http://www.fadr.msu.ru/o-washinet/spsynop.html .