Introduction

The Ring-billed Gull is a medium sized, white-headed, primarily inland nesting North American gull that frequents garbage dumps, parking lots, and southern coastal beaches in large numbers during the winter. This species was nearly decimated by human persecution and development from 1850 to 1920, but has since rebounded to become one of our most common and familiar birds. An estimated 3 to 4 million individuals inhabited North America in 1990. In some localities this gull is considered a pest and various measures are used to control its numbers, most with limited success. Based on morphology and display behaviors, it is closely related to other typical white-headed gulls; it has hybridized with Franklin’s and Laughing gulls.

An opportunistic feeder, the Ring-billed Gull prefers insects, earthworms, fish, rodents, and grain. It nests on the ground in colonies on sparsely vegetated islands in large lakes, and occasionally on mainland peninsulas and on near-shore oceanic islands. In the East, breeders share nesting habitat with Herring Gulls (Larus argentatus), in the Great Lakes area with Caspian and Common Terns (Sterna caspia and S. hirundo), in the west with California Gulls (L. californicus). Its breeding biology is well-known and the history of its populations during the last century well documented.

Based on morphological characters and display patterns, this gull is closely related to other typical white-headed gulls (Moynihan 1959b). Genetic analyses are required to establish its phylogenetic relationships with other gulls.

Important bibliographies on the Ring-billed Gull are: Clapp et al. (1983), which contains summaries of numerous aspects of the species’ biology with 276 references from 1907–1983; Smith (1986) lists 333 references between 1935–1986. The locations of spirit and skeletal collections are given in Wood et al. 1982a and 1982b respectively.