Parasitic Jaeger (Stercorarius parasiticus) -> Pallas's Gull (Stercorarius parasiticus) - BirdID's Bird Guide - Nord University

Species:

Parasitic Jaeger (Stercorarius parasiticus)

Pallas's Gull (Ichthyaetus ichthyaetus)

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Next species:

Long-tailed Jaeger

Common Gull

Prev species:

Pomarine Jaeger

Mediterranean Gull

Length (cm):

41-46

57-61

Wingspan (cm):

110-125

149-170

Weight (gram):

330-570

1100-1900

Size group:

Crow-size

Main Texts:

Appearance:

Dark, pale and intermediate morphs. Pale birds more common in northern parts of species range, darker morphs more common further south. Elongated middle tail feathers (projection comprising about half the total tail length), but not as long as in adult Long-tailed skua. White patches at base of primaries, both on upper and underside of wings. Dark morph chocolate brown with darker hood. Pale morph with white throat and belly and incomplete breast band. Relatively marked transition from pale belly to dark vent (as opposed to Long-tailed). Size close to Common Gull. Flight powerful, elegant and falcon-like. Juveniles with short but pointed middle tail-feathers. Confusion with other juvenile skuas very likely. Differs from Long-tailed in prominent white base of most primaries on upper side of wing (not just the first few feathers). Lacks the double white patch of Pomarine Skua's underwing, and shows less contrast between back and rump. Wings broader than Long-tailed but narrower than Pomarine. Approximately equal to distance from wing rear edge to tail-tip (projections excluded).

Sound:

Mostly heard at breeding ground. Most characteristic call is a mewing, kittiwake-like "aeeeee-ah". First syllable drawn-out and rising in pitch, and followed by a deeper conclusive second syllable "ah". Lacks the introductory double accent of Kittiwakes ("kitti-wake").

Alarm call/flight call: