Common Gull help, China (1 Viewer)

[xuky.summer]

I recorded a common gull today with lots of streaks on its head and neck and it looked very dirty, at first I thought it is kamtschatschensis, but went home and read the identification article by Peter Adriaens & Chris Gibbins and it seems that the wing pattern is more consistent with heinei? In my understanding, heinei is the whitest common gull in winter.
Shandon province.

 

[lou salomon]

Hi Xuki,

look at the little immaturity signs on primary coverts and alula - this should be a 3rd cycle type (for which obviously there is no key in Adriaens/Gibbins); but a discernible 3rd cycle is a hint towards kamtschatschensis. Furthermore: even a 2nd cycle heinei should be more white headed with dark shawl in winter, with a yellower bill and legs and no such white tongue to p7 (white between black subterminal mark and grey base). However, bill looks short and weak for kamtschatschensis. Small p9 mirror and large p5 subterminal black mark plus small mark to p4 are due to it being a subadult. So, on balance I tink this should be a small billed 3rd cycle kamtschatschensis.

 

[xuky.summer]

thank you lou!

 

[xuky.summer]

another gull, which ssp.

 

[lou salomon]

not quite sure on this bird as, a bit odd, adriaens-gibbins-key gives heinei for this bird (p4 with complete band, p8 without white tongue tip, p7 without white tongue tip, p9 mirror reaches onto outer web) but otherwise this bird has the typical immature look of kamtschatschensis with black even down to p1 - still underwing is little marked. I think it is a kamtschatschensis, but would of course like to hear Peter's (smiths) opinion here as there exist such retarded looking heinei.

 

[smiths]

I agree that the first bird (probably 3rd cycle) is most likely a Kamchatka gull, although it is difficult to exclude an intergrade with heinei since its slim body and thin bill with blackish bill band are more like that subspecies.

The 2nd-cycle bird should be a Kamchatka gull. I certainly don't see a white mirror on its P9, and it looks like there could well be a pale tongue-tip on P7 (if you look at the bird's left wing in photo 2608). Crucially, there seems to be a long, pale tongue on P8 (contra 2c heinei).
Second-cycle heinei can show such retarded plumage (even the odd canus can), but the 'frosty', pale fringes on the median and lesser coverts are typical of Kamchatka.
A retarded 2c heinei is shown in plate 45 in the 2016 Dutch Birding paper.

 

[xuky.summer]

Thank you very much! learn a lot.