The OSJ place Mongolian within Caspian thus Caspian is considered a regular winter visitor, however cachinnans still isn't listed in the most recent Japanese Check-List despite a number of claims over the years.
Last weekend I had a gull that strongly suggested cachinnans which would therefore be a mega here. There are a number of features which make me doubt it is a cachinnans but it was nevertheless much closer to that taxon than anything else that can be seen in Japan. I'd really appreciate some input from anyone with experience of them - I have zero.
Major worries are the extensive head streaking compared to images I've seen, the bill looks very deep with a distinct gonydeal angle and the primary projection doesn't look as long as I'd expect. Also the underparts are rather dark without a clean white centre running from the throat to vent. Lots of problems with this bird, yet a number of pro-cachinnans features which aren't shown by any gulls in Japan have got me toing and froing over this.
I've put a number of images along with shots of potential confusion taxa on my blog http://birdingkyoto.blogspot.jp/ and I'd really appreciate any help you guys can give.
Thanks very much,
Neil Davidson
Neil Davidson
Last weekend I had a gull that strongly suggested cachinnans which would therefore be a mega here. There are a number of features which make me doubt it is a cachinnans but it was nevertheless much closer to that taxon than anything else that can be seen in Japan. I'd really appreciate some input from anyone with experience of them - I have zero.
Major worries are the extensive head streaking compared to images I've seen, the bill looks very deep with a distinct gonydeal angle and the primary projection doesn't look as long as I'd expect. Also the underparts are rather dark without a clean white centre running from the throat to vent. Lots of problems with this bird, yet a number of pro-cachinnans features which aren't shown by any gulls in Japan have got me toing and froing over this.
I've put a number of images along with shots of potential confusion taxa on my blog http://birdingkyoto.blogspot.jp/ and I'd really appreciate any help you guys can give.
Thanks very much,
Neil Davidson
Neil Davidson