Caching Behavior in Free-Ranging White-Breasted Nuthatches: The Effects of Social Dominance

Abstract

Using five mated pairs of free-ranging White-breasted Nuthatches Sitta carolinensis, I examined whether the social dominance of the male nuthatch over the female affects the caching behavior of each individual of the pair. I allowed each bird of a mated pair in five deciduous woodlots in central Ohio to scatterhoard 30 mealworms Tenebrio sp. For each caching trip, I recorded data on 10 variables describing cache site characteristics and social context. I compared niche overlap and niche breadth values to determine the degree of sex-specific caching behavior. Nuthatches typically cached food items in bark crevices on the trunks of large, highly rugose trees. Both male and female nuthatches selected trees for cache placement that had higher than average rugosity. Departure directions from the food source differed significantly between the sexes when the male cached first. Males used the trunks of trees as a substrate for caching significantly more often than did females. By utilizing a broader caching niche, the females may have reduced interference competition from their mate, and thus may have compensated for their socially subordinate status.