adult common gulls are long, noticeably smaller than the herring gull and slightly smaller than the ring-billed gull. it is further distinguished from the ring-billed gull by its shorter, more tapered bill, which is a more greenish shade of yellow and is unmarked during the breeding season. the body is grey above and white below. the legs are greenish-yellow. in winter, the head is streaked grey and the bill often has a poorly defined blackish band near the tip, which is sometimes sufficiently obvious to cause confusion with ring-billed gull. they have black wingtips with large white "mirrors". young birds have scaly black-brown upperparts and a neat wing pattern, and grey legs. they take two to three years to reach maturity. the call is a high-pitched "laughing" cry.