The Occurrence of Unused Ring-Billed Gull Nests

Abstract

Bird are, with few exceptions, used solely for reproduction. However, male wrens (Troglodytes aedon and T. troglodytes) display and roost in nestlike structures called cock nests which they build in the vicinity of their active (Pettingill 1971). Tyrant flycatchers and woodpeckers construct refuge nests for roosting and shelter (Dorst 1974). Bobwhites (Colinus virginianus) build unused which probably represent structures or sites which are not suitable for the pair or they are associated with renesting or changes in suitable habitat (Stoddard 1936, Klimstra and Rosenberry 1975). Female Eastern Meadowlarks (Sturnella magna) commonly begin construction of several just before the female attains the sexual and physiological stage necessary for egg-laying (Saunders 1932, Rosenberry and Klimstra 1970). Tinbergen (1960) intimated a similar series of subliminal nesting drives to explain the existence of play nests of Herring Gulls (Larus argentatus). Harper (1971) reported similar structures in Western Gulls (L. occidentalis). Although the functional significance of unused is unknown in larids, they appear to represent repeated nest building activity which continues until an egg is laid (Tinbergen 1960, Harrington 1974). During ecological studies of Ring-billed Gulls (L. delawarensis) I noticed that some mated individuals built that were not used subsequently for egglaying. In this paper, I examine the frequency of these unused and their relationship to the hatching success of small groups of Ring-billed Gulls.