Slender-billed Gull Larus genei
1 adult winter moving into summer plumage, January 9th-11th, 2002, Gwangyang Bay, Jeollanam Province.
While scanning an assemblage of ca 1000 gulls, including ca 800 Black-headed Gulls Larus ridibindus on a shallow lagoon, with good light, one gull, about 200 m away from the observers (Nial Moores and Kim Su-Kyung) appeared obviously longer-necked than the otherwise rather similar Black-headed Gulls, as it fed by swimming and tilting to pick at items under the surface.
Identification was straightforward, however, as although it resembled the Black-headed Gulls around it, it was (1) slightly larger, and (2) it showed the long thin neck and bowed structure typical of Slender-billed Gull. In addition, (3) the head was largely unmarked (though showing a very small spot to the rear of the eye on closer views), (4) the bill was all scarlet-red (and long), darker distally. On the closed wing (5) the tertials were long, cloaking more of the primaries than is usual in Black-headed and (6) the primaries appeared all black (lacking the obvious white tips of Black-headed). At long range the eye appeared dark, but on closer views (closest down to ca 30 m, through 25x telescope in good light) it showed (7) a paler ’surface’. In addition, though not diagnostic, (8) the underparts were washed through with pink, strongest on the vent. In flight, (9) the primaries also showed a faint pink wash, while overall (10) it looked larger and faintly hump-backed.
The bird fed repeatedly by swimming, head and neck pushed forward, with its broader rear end upturned; occasionally it also picked items off the surface in more typical Black-headed Gull fashion, when it joined scavenging flocks.
The bird was photographed with a hand-held camera through a tripod-mounted telescope, and on the 11th by Busan Kukje Shinmun, a regional newspaper, which printed an article about the bird’s discovery including Nial Moores’s proposed Korean name: Giraffe-necked Gull.
Photo © Busan Kukje Shinmun
Although the Slender-billed Gull is a west Asian species (e.g. Grant 1986), it has been recorded several times in East Asia, most particularly in Hong Kong and in Japan. In Japan two birds were discovered wintering in Fukuoka City, Fukuoka Prefecture, with one returning to the same favored areas between 1984 and 1992 (Brazil, 1991 and pers obs). A second bird was also found in the Kitakyushu City area, Fukuoka Prefecture in the 1991/1992 winter (pers obs). NM has also seen the species once in the UK and in Spain.