Glaucous Gull Larus hyperboreus 北極鷗
Category I. Rare winter visitor to Deep Bay.
IDENTIFICATION
Jan. 2012, Michelle and Peter Wong. First-winter.
64-77 cm. Large gull the first and second-years of which have a combination of very pale primaries, clear-cut black tip to pink bill and generally pale buff or brown plumage; both age classes can fade to almost white at the end of the winter.
Adult in non-breeding plumage has pale grey upperparts fading to whitish-grey on primaries, white trailing edge to secondaries and inner primaries and extensive brown streaking on head and blotches from nape to upper chest. Third-year similar to adult but often has brownish wash or marks on upper wing coverts, primaries and tail, and blackish in bill.
Jan. 2012, Michelle and Peter Wong. First-winter.
In flight appears very pale, particularly on the primaries and secondaries.
VOCALISATIONS
Similar to other large gulls.
DISTRIBUTION & HABITAT PREFERENCE
All records have occurred in Deep Bay apart from the first, which was seen in Victoria Harbour off the former airport at Kai Tak.
OCCURRENCE
There have been 11 records since the first on 15 March 1974 (Melville 1977) in the period from 14 December to 3 April, though mostly from 21 January. Apart from second-year birds in 1994 and 1999, all were first-years.
BEHAVIOUR, FORAGING & DIET
No information.
RANGE & SYSTEMATICS
Has a circumpolar breeding distribution mainly north of the Arctic Circle; winters regularly as far south as 35oN (Weiser and Gilchrist 2020). In China winters coastally south to Hainan (Liu and Chen 2020), though based on Hong Kong records it is rare this far south.
Four subspecies are recognised of which L. h. pallidissimus is the most likely to occur as it breeds from northwest Siberia to the Bering Sea; the nominate breeds west of there to northern Europe, while the remaining two subspecies breed from Alaska to Iceland.
CONSERVATION STATUS
IUCN: Least Concern. Population trend stable.
Liu, Y. and Chen, Y. H. (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Melville, D. S. (1977). New Laridae records from Hong Kong. Bull. B.O.C. 93: 34-37.
Weiser, E. and H. G. Gilchrist (2020). Glaucous Gull (Larus hyperboreus), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.glagul.01
