This first-cycle large gull was photographed at Brownsville Landfill, Cameron county, Texas on February 08, 2014; it shows some features suggestive of Kelp Gull, but the strongly-marked fresher scapular and upperwing coverts feathers are a minority pattern, and perhaps the dark marks on the rump are not good for that taxon ("V"-shaped rather than a bar). However the bill shape, rear-end structure (wing tip vs tail tip vs tertail tip), and tail pattern favor Kelp over LBBG. Also the stage of molt seems more typical of April/May than early February. It may be a hybrid involving Kelp, but I see no obvious features of American Herring Gull - ?
CLICK HERE and HERE and HERE and HERE and HERE and HERE to see Kelps with 2nd/3rd generation upperparts feathers similar to this bird. ALSO look at the comparison pics at the bottom of this page to see two birds that have similar features to this individual:
I don't normally upload pics without permission, but I've tried hard to locate the following two images on the Web, without success (I downloaded them more than a year ago!) - and they both have such striking similarities with the bird above that I am making an exception. If anyone knows where these images reside on the Web, please contact me, thanks:
Compare the above bird to this photo of a Kelp Gull from Peru; note the head and bill shape and pattern.
Compare the upperparts feathers to the Brownsville bird: