Caspian Gull in Japan? (1 Viewer)

[neilcd21]

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

 

[JANJ]

Hi Neil!

Although Caspian certainly is on the Japan list, one adult which I have seen on the Ujihara´s site a while ago, which btw we europeans don´t have access to at the moment (the americans have). There are - as you mention - some Caspian features to your gull, however, it doesen´t strike me as one all the way. It would be quite unusual for a 1 cycle taimyrensis type at this time of year to show such an advanced moult. The 2nd generation scapulars with dark shatft streak is perhaps more in line with heuglini/taimyrensis. Could it be an advanced taimyrensis? Compare with Caspian Gulls here:http://gull-research.org/cachinnans/01cynov.html
And also some Mars taimyrensis types here:http://www.pbase.com/smiths_1/taimyr_gull
Lets see...
JanJ

 

[neilcd21]

Hi Neil!

Although Caspian certainly is on the Japan list, one adult which I have seen on the Ujihara´s site a while ago, which btw we europeans don´t have access to at the moment (the americans have). There are - as you mention - some Caspian features to your gull, however, it doesen´t strike me as one all the way. It would be quite unusual for a 1 cycle taimyrensis type at this time of year to show such an advanced moult. The 2nd generation scapulars with dark shatft streak is perhaps more in line with heuglini/taimyrensis. Could it be an advanced taimyrensis? Compare with Caspian Gulls here:http://gull-research.org/cachinnans/01cynov.html
And also some Mars taimyrensis types here:http://www.pbase.com/smiths_1/taimyr_gull
Lets see...
JanJ

Hi Jan,
Thanks for commenting.

I didn't think it was a typical Caspian really but needed advice not having seen any and being unaware how much variation is possible. The moult timing is quite exceptional I think, probably there months ahead of typical birds which is a long time at that (any) age.

The Ujiharas have had at least one Caspian, the most recent 2007, but the latest Japan List (published 2012) includes Caspian in Appendix B (presently unacceptable) which is presumably a technicality as Ring-billed and California are also included there.

Cheers - Neil