Territory Size in Wintering Sanderlings: The Effects of Prey Abundance and Intruder Density

Abstract

Winter territory size in the Sanderling (Calidris alba) on marine beaches varies inversely with prey density. Multivariate analyses suggest that the inverse correlation results indirectly because more intruders are attracted to areas of higher prey density, and increased intruder frequency makes territorial defense more costly. Once the interaction between prey density and intruder density is controlled statistically, prey density has no effect on territory size.