Relict Gull Icthyaetus relictus 遺鷗
Category I. Rare winter visitor to intertidal mudflats of Deep Bay.
IDENTIFICATION
Jan. 2008, Kinni Ho. First-winter.
39-45 cm. Structurally distinct due to relatively small head, rather flat crown that peaks behind eye, small eyes, thick neck, and large, pot-bellied body. Slightly awkward gait at times.
First-winter birds typically occur. These are pale grey above with whitish-fringed tertials, pale brown in the lesser and median coverts and narrow brown streaks at the rear and sides of the neck; these brown areas fade quite quickly in the winter. Bill has a pale greenish-grey basal half to two-thirds. Upperpart, wing and tail feathers prone to wear and fading.
Jan. 2015, Michelle and Peter Wong. First-winter.
In flight first-winters are rather pale with contrasting dark brown outer four primaries, subterminal marks on the inner primaries and secondaries, greater coverts and tail band, and white mirrors on outer 1-2 primaries
Adults in breeding plumage have a blackish brown hood that is paler around the base of the bill, and bright red legs and bill.
VOCALISATIONS
Calls include a rather deep ‘kyeeow’ and a donkey-like bray.
DISTRIBUTION & HABITAT PREFERENCE
All records refer to birds seen on the intertidal mudflats of Deep Bay from the Mai Po Boardwalk apart from one at Lau Fau Shan.
OCCURRENCE
All records have involved first-year birds in the period 3 November to 12 April, but mainly from early January to early March.
1987: 31 December 1987 and 2 January 1988 (Kennerley 1990).
1992: two birds, the first from 21 November 1992 to 8 March 1993, and the second from 28 November to 5 December.
2006: one on 22 and 30 March.
2008: up to two from 13 January to 2 March.
2010: one from 8 January to 10 March.
2011: one during 8-12 April.
2015: one from 11 January to 14 March.
2016: one on 24th and 26 December.
2017: one on 3 November.
BEHAVIOUR, FORAGING & DIET
Walks around mudflat foraging in the manner of an ungainly plover.
RANGE & SYSTEMATICS.
Monotypic. Breeds from east Kazakhstan east through much of Mongolia and in Inner Mongolia, where largest colonies are thought to exist (Burger et al. 2020). In China breeds in north Xinjiang and from Shaanxi to central and east Nei Mongol and winters in the Yellow Sea (Liu and Chen 2020), particularly the Bay of Bohai.
CONSERVATION STATUS
IUCN: VULNERABLE. Population, which is estimated at 10,000 to 19,999, anticipated to undergo rapid decline in next three generations due to human disturbance at nesting colonies, climate change and threat of reclamation of coastal mudflats where bulk of population spends the winter.
Burger, J., M. Gochfeld, C. J. Sharpe, and E. F. J. Garcia (2020). Relict Gull (Ichthyaetus relictus), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.relgul2.01
Kennerley, P. R. (1990). Relict Gull at Mai Po. The first record for Hong Kong. Hong Kong Bird Report 1989: 80-91.
Liu, Y. and Y. H. Chen (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
