Two gulls - Lake Geneva, Switzerland (1 Viewer)

[SternaParadisaea]

Yesterday, I observed these two birds among (very common) Yellow-legged Gulls. What are your thoughts?

First bird:







This bird looked darker than usual 1st winter YLG. As the inner primaries look dark and the black stripe on the tail looks wide, I am inclined to think that it could be a Lesser black-backed Gull. Furthermore, the 2nd generation feathers on the scapular seem to match better the pattern usually seen in LBBG that the one of YLGs, and the underwings are dark. However, the structure does not seem to match completely with the typical LBBG. Especially, the bill looks quite strong (even if on the field, the structure also looked a bit different - smaller and thinner - compared to YLGs). I think that the pattern of molt cannot help, as it is (in mid-winter) similar between both species.

Second bird:



That is for sure a 1st winter bird (shape of primaries). The structure here is consistent with a YLG, but what about the plumage? It seems intermediate between Caspian and YLG, or even closer to Caspian except the head... Can it be a hybrid?

I wish you a very good evening!

 

[lou salomon]

Sorry to disappoint you but both birds look good for YLG, all within variation. Bill and general structure in the first as well as regular barred (double anchors) 2nd gen. scapulars, greater covert bar not with blackish parts, worn plumage - all good for michahellis. Note that tail bands habitually look broader when seen from the side. And the second one just has pretty plain scapulars, in cachinnans style, but nothing unusual in YLG. Bill, general structure and greater coverts give it away.

 

[SternaParadisaea]

Thank your for your reply! Interesting to see the large amount of variation between two birds that have the same age