Note how thin the legs are when seen from directly behind in the photo below; also note the longer legs compared to the first-winter smithsonianus to the left, which is standing at the same distance from the camera:
Note below the strongly blackish front to the tarsi; Note that size comparisons cannot be made with the smith. on the right as it is standing some distance behind (the target bird is stood on the top of a slight ridge in the middle of the sandbar):
The pic below conveys the rather rakish appearance of the legs that was apparent in the field (plus again the black front to each tarsus):
This bird was very restless, aways moving around and pecking at something, while the other gulls were resting. All the gulls sit on a large sandbar just north of a low, wave-swept sea wall - even when flushed by cars, dogs, people, or the rising tide, I've never seen any of the large gulls even attempt to land on the sea wall (with acres of sandbar to choose as their preferred loafing habitat)... This bird responded a couple of times to my approach by flying in a large circle and landing back on the same sandbar, but then flew over and landed on the seawall, walking along it (hopping the occasional wave) and pecking at the algae on the concrete, as were a few Laughing Gulls:- in my experience this is an odd behavior for any of the large gulls we normally get on the Texas coast (including LBBGs) :