Herring gull, the birds most commonly called seagulls, are gray and white with pink legs. Adult birds measure between 22 and 26 inches in length and appear heavy for their size. The birds have thick, medium-length beaks.
Juvenile herring gulls change colors and can have mottled brown, brown and gray, or gray and white feathers, depending on the age of the bird. Adult seagulls have gray feathers on their backs and black feathers on the tips of their wings. During winter, the birds' white heads have streaks of darker feathers. Seagulls have loud calls and engage in competitive scavenging behaviors.