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Haliaeetus pelagicusSteller's sea eagle(Also: Steller's sea-eagle)

By Danielle Nelson

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. (Collar, 2001)

  • Aquatic Biomes
  • rivers and streams
  • coastal
  • Range elevation
    0 to 100 m
    0.00 to 328.08 ft

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999; Brown and Amadon, 1989)

  • Sexual Dimorphism
  • female larger
  • Average mass
    males - 6, females - 9 kg
    lb
  • Range length
    85 to 94 cm
    33.46 to 37.01 in
  • Average wingspan
    males - 118, females - 136 cm
    in

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999; Collar, 2001)

  • Breeding interval
    Steller's sea eagles breed once yearly.
  • Breeding season
    Breeding occurs from February through August.
  • Range eggs per season
    1 to 3
  • Range time to hatching
    38 to 45 days
  • Average fledging age
    70 days
  • Average time to independence
    70 days
  • Range age at sexual or reproductive maturity (female)
    6 to 7 years
  • Range age at sexual or reproductive maturity (male)
    6 to 7 years

At this time, little is known about the parental investment of Steller's sea eagles. Both parents contribute to raising offspring to independence. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

  • Parental Investment
  • 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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. (Collar, 2001)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999; Brown and Amadon, 1989)

  • Animal Foods
  • birds
  • mammals
  • fish
  • 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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

Ecosystem Roles

Steller's sea eagles are important predators of salmon and other prey in their native ecosystems. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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. ("BirdLife International Species factsheet: Haliaeetus pelagicus", 2007; "Species Synopsis Stellar Sea Eagle", 1999)

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.

Contributors

Tanya Dewey (editor), Animal Diversity Web.

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

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

estuarine

an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

freshwater

mainly lives in water that is not salty.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

scavenger

an animal that mainly eats dead animals

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

References

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.

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.

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