Slaty-backed Gulls

Given the recent putative Slaty-backed Gull in London, I paid close attention to the Slaty-backed Gulls in Choshi. I saw around 45 examples of what I identified as Slaty-backed and photographed several. As with most gulls, this species is variable and, although there are a suite of features (eg pale eye, dark ‘intermedius LBBG-coloured’ mantle, shortish raspberry pink legs, pale yellow bill etc) that distinguish a typical Slaty-backed, there appear to be many examples with one or more of these features lacking. Below is a selection of my images of Slaty-backed Gulls with some associated personal comments. I am in no way qualified to comment on the London bird, except to say that if I saw it at Choshi I wouldn’t have hesitated to identify it as a Slaty-backed.

Please contact me if you spot any inaccuracies in my commentary or have any additional comments.

The first Slaty-backed Gull I saw. This individual has a relatively bright bill

No2: looks dark-eyed but in the field the iris was pale-ish, albeit heavily speckled

No3: a typical individual with a pale eye, dark (Lesser Black-backed-coloured) mantle and strong bright pink legs

No3 in flight: same bird as above. Mantle appears lighter at the different angle.

No4: from below

No5: from above. The mantles of some birds look relatively pale in strong light. Note no mirror on p9.

No5: Same bird.

No5: close up of head and underwing pattern. Eye is speckled and could appear dark at distance.

No6: a dark bird with heavy head streaking. 'String of pearls' obvious.

No7: an immature bird but note very pale underwing in strong light.

No7: Same as above. Note how the underwing looks darker in different light.

No8: the legs appear relatively pale and thin (taken in strong light)

No9: eye appears dark. mirrors on p10 and p9.

No9: Same individual as above. Eye looks paler in strong light.

No10: Eye looks dark on this individual. Bill pale yellow with slightly brighter tip.

No11: 'String of pearls' clear on this bird. Heavy streaking on the head.

No12: A typical individual in terms of mantle colour, pale eye, primary pattern and leg colour.

No12: same individual as above next to a Vega Gull (with Black-tailed Gull behind) for comparison.

No13: Pale eye, dark mantle and relatively heavy head streaking.

No13: Same bird as above. Note no mirror on p9.

No14: Typical. Pale yellow bill, sturdy bright pink legs.

No14: same bird as above in flight. 'String of pearls evident, large mirror on p10 with smaller mirror on p9.

No15: Note no mirror on p9.

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About Terry Townshend

I am a British birder living and birding in Beijing from August 2010 until 2015. Through this blog I hope I can convey a sense of what it is like to live in this thriving, confident and contrasting city and the birdlife that can be found in its environs. I hope you enjoy reading it as much as I enjoy writing it! Terry Townshend, Beijing September 2010
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One Response to Slaty-backed Gulls

  1. Pingback: Tweets that mention Slaty-backed Gulls | Birding Beijing -- Topsy.com

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