An adult Ring-billed Seagull [Larus delawarensis] in flight, by Jiyang Chen. Seagulls are most closely related to the terns (family Sternidae) and only distantly related to auks, skimmers, and more distantly to the waders.
Noisy birds, they eat anything. Did you know that if you toss food (or peanuts) into the air they will swoop them up. We used to love doing that in Golden Gate Park, San Francisco. There are even seagulls inland like Utah.