Photo: Dan Irizzary/Flickr Creative Commons

Pomarine Jaeger

Stercorarius pomarinus

Powerful and fast-flying, a predator and pirate of the ocean and the far north. The largest of the three jaeger species. Not seen from shore as often as Parasitic Jaeger, but usually the one seen in greatest numbers on boat trips offshore. In northern Alaska, this is a major predator on the brown lemming: During summers when these rodents are in low numbers, many Pomarine Jaegers do not attempt to nest.
Conservation status Local breeding numbers fluctuate strongly along with population cycles of lemmings and other rodents. Worldwide jaeger population difficult to monitor, but no evidence of major declines. Most of breeding range is remote from impacts of human activity.
Family Skuas and Jaegers
Habitat Open sea, coasts (offshore); tundra (summer). Spends most of year at sea, often over continental shelf, but usually stays farther from land than Parasitic Jaeger and may occur far out in mid-ocean. Concentrates over upwellings and boundaries of currents. In summer on tundra, generally low-lying areas near coast.
Powerful and fast-flying, a predator and pirate of the ocean and the far north. The largest of the three jaeger species. Not seen from shore as often as Parasitic Jaeger, but usually the one seen in greatest numbers on boat trips offshore. In northern Alaska, this is a major predator on the brown lemming: During summers when these rodents are in low numbers, many Pomarine Jaegers do not attempt to nest.
Photo Gallery
  • adult, breeding, light morph
  • adult, breeding, dark morph
  • immature
  • dark adults
  • adult, breeding, light morph
Feeding Behavior

Forages at sea by dipping to surface in flight to catch fish, by catching small birds in flight, also by harassing other birds and forcing them to drop their food. Forages over land mostly by hovering and dropping on prey.


Eggs

2, rarely 1-3. Olive to brown, blotched with dark brown. Incubation is by both parents, 25-27 days. Young: May leave nest a few days after hatching, but remain in general area, are fed by both parents. Age at first flight about 31-27 days; dependent on parents at least 2 more weeks.


Young

May leave nest a few days after hatching, but remain in general area, are fed by both parents. Age at first flight about 31-27 days; dependent on parents at least 2 more weeks.

Diet

Includes fish, rodents, birds. Diet varies with location. At sea, usually eats fish, also smaller birds and some carrion or refuse. Breeding birds feed heavily on lemmings and other rodents; non-breeding birds in summer around tundra have more varied diet, including birds, eggs, fish, carrion, insects.


Nesting

At least in some regions, much more likely to nest in years when rodent populations are high. Birds younger than 4-5 years old attempt nesting only in such good seasons. Defends nesting territory against other species of jaegers. In courtship, members of pair face each other, vibrating wings and calling. Male may feed female. Nest site is on open ground, sometimes on slightly raised ridge or hummock. Nest (built by both sexes) a shallow depression, often lined with bits of plant material.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Most migration is offshore. Migrates later in fall than other jaegers, especially young birds, with juveniles rarely seen south of the Arctic before October. Some apparently migrate to far southern oceans, but others remain off North American coasts in winter. Very rare inland, but such strays may appear in summer as well as during migration seasons.

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Migration

Most migration is offshore. Migrates later in fall than other jaegers, especially young birds, with juveniles rarely seen south of the Arctic before October. Some apparently migrate to far southern oceans, but others remain off North American coasts in winter. Very rare inland, but such strays may appear in summer as well as during migration seasons.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon
Songs and Calls
Harsh chattering calls; a harsh which-yew.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How climate change could affect this bird's range

In the broadest and most detailed study of its kind, Audubon scientists have used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change.

Learn more

Read more: climate.audubon.org
Gulls and Terns Gull-like Birds

Pomarine Jaeger

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season.

More on reading these maps.

Each map is a visual guide to where a particular bird species may find the climate conditions it needs to survive in the future. We call this the bird’s “climatic range.”

The colors indicate the season in which the bird may find suitable conditions— blue for winter, yellow for summer (breeding), and green for where they overlap (indicating their presence year-round).

The darker the shaded area, the more likely it is the bird species will find suitable climate conditions to survive there.

The outline of the approximate current range for each season remains fixed in each frame, allowing you to compare how the range will expand, contract, or shift in the future.

The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

You can play or pause the animation with the orange button in the lower left, or select an individual frame to study by clicking on its year.

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.
Winter
Summer

Winter Range
Summer Range
Both Seasons
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