Parasitic Jaeger

Stercorarius parasiticusOrder: CHARADRIIFORMES Family: Skuas, Gulls, Terns, Skimmers (Laridae)

Codes: Common Name: PAJA Scientific Name: STEPAS ITIS Taxonomic No.: 176793

Breeding Location:

Tundra

Breeding Type:

Monogamous, Colonial

Breeding Population:

Fairly common, Stable

Egg Color:

Brown to green or blue, with brown spots

Number of Eggs:

Incubation Days:

25 - 28

Egg Incubator:

Both sexes

Nest Material:

Lined with plant material.

Migration:

Migratory

General

Parasitic Jaeger Dark Morph: Medium-sized jaeger with brown body, darker cap, and pale underwing patches near tips. Light morph has white underparts with brown breast band; intermediates between dark and light morphs occur. Diamond-shaped tail has elongated, pointed central feathers. Sexes are similar. Juveniles of both morphs are brown-barred overall and have dark-tipped bills and slightly elongated central tail feathers.

Range and Habitat

Parasitic Jaeger Dark Morph: Breeds on coasts of Alaska, as well as coastal and inland tundra regions of northern Canada; also found in Greenland, Iceland, Scandinavia, and northern Russia. Spends winters on tropical oceans of the southern hemisphere.

Breeding and Nesting

Parasitic Jaeger Dark Morph: Two brown to green or blue eggs with brown spots are laid in a shallow ground depression lined with plant material. Incubation ranges from 25 to 28 days and is carried out by both parents.

Foraging and Feeding

Parasitic Jaeger Dark Morph: Eats small and medium-sized birds, bird eggs, insects, fish, rodents, and carrion. Hunts cooperatively, with one chasing a bird near the ground while another flies above to intercept dodges; also, one distracts incubating parent while the other makes off with an egg. Sometimes harasses other birds, forcing them to release small fish or other food held in their bills or crops.

Vocalization

Parasitic Jaeger: Usually silent; on breeding grounds utters a series of repeated two-syllable notes and a variety of mewing sounds.

Similar Species

Parasitic Jaeger Dark Morph: Long-tailed Jaeger is pale gray above and lacks breast band. Pomarine Jaeger is larger and bulkier with rounded central tail feathers.

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Bird Call Credits: The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology. Martyn Stewart, http://www.naturesound.org, Redmond, Washington USA. The reuse or copying of bird calls in this database is strictly forbidden.

Parasitic Jaeger

Parasitic Jaeger Dark Morph: Medium jaeger with brown body, darker cap, and pale underwing patches near tips. Pale form has white underparts with brown breast band; intermediates between dark and light morphs occur. Diamond-shaped tail has elongated, pointed central feathers. Black bill, legs, feet.

● Song: "skooo-a", "ka-aaow"

● Foraging & Feeding: Parasitic Jaeger Dark Morph: Eats small and medium-sized birds, bird eggs, insects, fish, rodents, and carrion. Hunts cooperatively, with one chasing a bird near the ground while another flies above to intercept dodges; also, one distracts incubating parent while the other makes off with an egg. Sometimes harasses other birds, forcing them to release small fish or other food held in their bills or crops.

● Breeding & nesting: Parasitic Jaeger Dark Morph: Two brown to green or blue eggs with brown spots are laid in a shallow ground depression lined with plant material. Incubation ranges from 25 to 28 days and is carried out by both parents.

● Similar species: Parasitic Jaeger Dark Morph: Long-tailed Jaeger is pale gray above and lacks breast band. Pomarine Jaeger is larger and bulkier with rounded central tail feathers.

Flight Pattern

Alternates several deep flaps with glides., Fast wing beats.

● Range & Habitat: Parasitic Jaeger Dark Morph: Breeds on coasts of Alaska, as well as coastal and inland tundra regions of northern Canada; also found in Greenland, Iceland, Scandinavia, and northern Russia. Spends winters on tropical oceans of the southern hemisphere.

^BreedingMonogamous, Colonial

^PopulationFairly common, Stable

^MigrationMigratory

^Weight14.9 Ounces

Underparts

Belly, undertail coverts, chest, flanks, and foreneck.

Breast

The upper front part of a bird.

Cap

The area on top of the head of the bird.

4 and 6 letter alpha codes

The four letter common name alpha code is is derived from the first two letters of the common first name and the first two letters of common last name. The six letter species name alpha code is derived from the first three letters of the scientific name (genus) and the first three letters of the scientific name (species). See (1) below for the rules used to create the codes..

Four-letter (for English common names) and six-letter (for scientific names) species alpha codes were developed by Pyle and DeSante (2003, North American Bird-Bander 28:64-79) to reflect A.O.U. taxonomy and nomenclature (A.O.U. 1998) as modified by Supplements 42 (Auk 117:847-858, 2000) and 43 (Auk 119:897-906, 2002). The list has been updated by Pyle and DeSante to reflect changes reported by the A.O.U from 2003 through 2006.

Field Guide to Birds of North America