Birds of Oman

(singke) #1

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PLATE 57: SMALL AND PELAGIC TERNS


Little Tern Sternula albifrons mb
L: 23. W: 53. Small with fast wingbeats. Adult in summer is pale grey above, extending in some onto
centre of otherwise white rump; usually two grey-black leading primaries (with white shafts);
white forehead usually extending in point to rear of eye; legs bright yellow to reddish-orange.
In winter, bill black, legs dull grey or brown, usually with some yellow; black on head reduced to
band around nape; rump and tail largely grey. Juvenile (dark bill with reddish base) has dark ‘U’-
shaped markings on pale grey mantle, scapulars and tertials, lost in first winter when resembles
winter adult; legs greyish-pink to yellow-brown; upperwing shows dark outer primaries becoming
progressively paler inwards; leading forewing dark. Voice Excited, hoarse grating kryik or pret-pret.
Habitat Coastal and inland waters; nests on beaches or sandbanks in rivers. Note Passage hatched;
winter range obscured by confusion with Saunders’s Tern; vagrant Yemen.

Saunders’s Tern Sternula saundersi RB, PM, WV
L: 22. Separation from Little Tern problematic. In summer, upperparts contrast markedly with
blacker outer three primaries (dark-shafted); white forehead not usually reaching eye thus
squarer; rump more extensively grey than in Little and concolorous with back; legs generally
darker, reddish- or pinkish-brown, sometimes some yellow on rear tarsus. In winter, adult and
first-winter birds doubtfully separable (Saunders’s has darker grey upperparts than similar-aged
Little in Red Sea; apparently not so in Arabian Gulf). Voice Strident calls recall Little closely, but
often lacking same urgency; sharp kip or wip, and excited tchijjick. Habitat Coastal, rarely inland;
nests on beaches. Note Winters on Iranian and Arabian coasts.

Bridled Tern Onychoprion anaethetus MB, PM
L: 37. W: 76. Medium-sized slender tern, Sooty Tern being the confusion species. Dark ashy
upperparts (but often appearing blackish), narrow white forehead-band extending behind eye as
narrow supercilium, black cap contrasting with pale grey hindneck-collar and greyer mantle (often
hard to see in flight); long outer feathers of deeply forked tail have white sides. Whitish underparts
and underwing-coverts contrast with dark silver-grey central tail feathers and especially flight
feathers. Underparts can appear grey. Juvenile lacks distinct supercilium, has pale grey-brown back
and wing-coverts, edged buffish. Flight graceful with slimmer wings than Sooty Tern. Does not
dive but takes food from surface of water. May settle on sea, with tail pointing upwards at 45°.
Voice High-pitched kee-yharr, yelping wep-wep and a harsh grating karr; also a pleasing rolled
purrurr or prerrr, given day or night at sea or in colony. Habitat Maritime; breeds colonially on rocky
or sandy islands, in crevices or under low vegetation. Note Passage hatched; winters in Arabian Sea.

Sooty Tern Onychoprion fuscata mb
L: 44. W: 90. Larger, more stocky than Bridled Tern and with entire upper surface uniform blackish
(paler mantle and hindneck in Bridled), broader but shorter white forehead-patch than Bridled
(not extending beyond eye), and black loral streak reaching gape (not base of upper mandible as
in Bridled); white underparts and underwing-coverts contrast more with dark grey flight feathers,
outer primaries lacking whitish wedge towards wing-tip. Juvenile sooty-brown all over except
for whitish belly and undertail-coverts; upperparts flecked whitish. Told from young Brown and
Lesser Noddies by whitish vent and undertail-coverts, paler underwing and forked tail. First-summer
like adult but throat and upper breast blackish. May settle on sea surface, as Bridled Tern. Voice Call
diagnostic, a high-pitched ker-wacki-wah. Habitat Maritime; nests colonially in open on sandy, rocky
or vegetated islands. Note Dispersal as hatched, but rare; vagrant Bahrain, Iran, UAE.
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