It's a good example of a 1st year Slaty-backed gull.
In flying, the bird shows well its wing and tail patterns.
First of all the upper wing: the dark secondaries forming a broad trailing edge contrasting with the wing coverts is a good point.
For underwing, the dark coverts contrasting with pale flight feathers but a clear dark line forming along primary tips is also a good
point.
For upper tail, the photos show a broad dark band but tail coverts also well marked together is the third indicator.
For the rest: darkish heavy bill, black mark around eye and heavily and darkly marked belly seal its identity.
Besides, I find the wings while quite wide, are pointed towards tips. And it's obvious the gull is heavy-keeled.
S L Tai
[ Last edited by tsheunglai at 7/04/2013 21:27 ]