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Parasitic Jaeger Life History



They breed on the Arctic tundra and spend the rest of the year at sea.

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Breeding Parasitic jaegers eat mainly adult, young, and eggs of shorebirds, waterfowl, terns, and songbirds. They also eat insects, small mammals, berries, carrion, and offal. When on the ocean, they harass other seabirds until they give up their catch.

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Nest Placement


They nest on depressions or hollows on the ground, usually on a slight rise, in the tundra.

Nest Description

The birds make a nest by pressing down the vegetation around the nest site using their breast and feet. They sometimes line the nest with dry grass, lichens, or twigs. They occasionally use bare ground.

Nesting Facts

Clutch Size:1-2 eggs
Number of Broods:1 brood
Egg Length:2.0-2.4 in (5.1-6.1 cm)
Egg Width:1.5-1.7 in (3.8-4.3 cm)
Incubation Period:24-29 days
Nestling Period:2 days
Egg Description:

Greenish to brownish olive, blotched with brown.

Condition at Hatching:

Downy and ready to leave the nest in a couple of days.

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Aerial Forager

Jaegers are spectacular aerialists that gain much of their food by pursuing seabirds until they give up or regurgitate their catch. Pair bonds often last for several years as long as both male and female survive and return to the breeding grounds. Pairs split up after the breeding season and generally remain apart through the year, re-forming at the beginning of the next breeding season.

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Low Concern

Parasitic Jaegers are fairly numerous and widespread. Partners in Flight estimates the global breeding population at 3.5 million. They score a 9 out of 20 on the Continental Concern Score, which means they are not on the Partners in Flight Watch List and are a species of low conservation concern.

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Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Mullarney, K., L. Svensson, D. Zetterström, and P. Grant (1999). Collins Bird Guide. HarperCollins Publications Ltd., London, United Kingdom.

Wiley, R. Haven and David S. Lee. (1999). Parasitic Jaeger (Stercorarius parasiticus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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Learn more at Birds of the World