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PLATE 59: SKUAS
South Polar Skua Stercorarius maccormicki V
L: 53. W: 127. Closely resembles Brown Skua. Pale and intermediate morphs identifiable by creamy
buff or grey-brown head, hindneck and underparts, contrasting with blackish underwing-
coverts. Dark morph often has pale forehead, hindneck with pale wash at sides and bill sometimes
more bicoloured. During primary moult (July–August) immature may have conspicuous symmetrical
gaps in each hand. Pale ‘noseband’ at base of upper mandible shown by some birds. Habitat
Maritime. Note Vagrant Oman, Yemen.Brown Skua Stercorarius antarcticus V
L: 63. Larger and darker than South Polar Skua, with broad-based wings, heavier bill, and lacking
contrasting paler head and underbody, both species showing conspicuous white primary patches
(above and below) even at long range. Adult very similar to dark morph of South Polar Skua, but
upperparts less uniform with prominent pale mottling and flecking (but only visible at close range).
Juvenile warmer in tone without heavy mottling above. Some individuals cannot be safely told
from South Polar Skua. Typically thicker-billed and darker chocolate-brown than extralimital Great
Skua Stercorarius skua, but latter not a reliable or constant field character. Habitat Maritime. Note
Vagrant Oman; vagrant unidentified large skuas in Iran and UAE also considered to be this species.Pomarine Skua Stercorarius pomarinus PM, wv, sv
L: 51–56. W: 125. Size of large gull, heavily built and, in adult, elongated broad and twisted central
tail feathers (‘spoons’) diagnostic, though these are often lost. Two morphs: dark (scarce) and pale
morph, which differs from Arctic Skua in more extensive black cap, darker flanks and blacker breast-
band (sometimes absent) and vent. In winter, flanks and tail-coverts barred, elongated tail feathers
often short and always blunt-ended. Juvenile best separated from similar Arctic Skua by more
regular bars on flanks, vent, rump and tail-coverts. Whitish base to greater primary coverts below
often conspicuous, even at range (frequently absent in Arctic Skua). Bill proportionately larger,
heavier at base and more distinctly bicoloured. With experience can be identified by larger size,
slower wingbeats, broader wings, deeper breast and belly; also, in juvenile, when present, short,
blunt central tail feathers (pointed in Arctic Skua). Piratical attacks more direct, less agile than
Arctic, frequently chasing large gulls. Habitat Maritime. Note Passage hatched; winters mostly in
Arabian Sea. [Alt: Pomarine Jaeger]Arctic Skua Stercorarius parasiticus PM, wv, sv
L: 46. W: 117. Streamlined appearance in flight, appearing intermediate in size and proportions
between Pomarine and Long-tailed Skuas. Adult in summer has elongated, pointed central tail
feathers (6–11cm). Two morphs occur (dark and pale), with frequent intermediates. Juvenile
variable, from pale to very dark birds; ground colour generally warmer, more rusty than young
Pomarine Skua; juvenile told with experience from young Long-tailed Skua by broader wings,
slightly shorter tail (equals width of wing-base), shorter, pointed central tail feathers (longer,
blunt-ended in Long-tailed), thicker rear-body, less black on bill-tip and warmer brownish ground
colour (colder, greyer in Long-tailed Skua), with rusty fringes and barring. Normal flight steady,
falcon-like, straight and fast; piratical attacks with sudden twists and turns, harassing birds the
size of Sandwich Tern or Common Gull. Habitat Maritime. Note Passage hatched; winters mostly in
Arabian Sea. [Alt: Parasitic Jaeger]Long-tailed Skua Stercorarius longicaudus V
L: 53. W: 111. Slim and lightly built; size of Black-headed Gull. Resembles pale and rather grey Arctic
Skua but adult told by very long, flexible central tail feathers (16 –24cm), lack of breast-band,
white forebody gradually darkening towards rear, pale greyish upperparts contrasting with
blackish flight feathers with pale shaft streaks only on outermost primaries, and pale blue-grey
legs. Juvenile variable like young Arctic Skua, but has colder, greyer ground colour and fringing
(never rusty), more distinct barring on uppertail-coverts (except in darkest birds), thin white shaft-
streak in leading primaries (hardly visible beyond 500m, unlike distinct white flash on most Arctic
Skuas) and blunt-ended central tail feathers. Primaries on settled bird are plain (broad buffy tips
on Arctic). At rest shows more rounded head and shorter, proportionately thicker bill with black tip
to half the length, unlike Arctic Skua. Also relatively deeper-chested with thinner rear-body. Flight
more buoyant and tern-like than Arctic Skua; includes more circling and hovering, without making
aggressive piratical attacks. Habitat Maritime. Note Vagrant Iran, Kuwait, Oman, Qatar, UAE. [Alt:
Long-tailed Jaeger]