Individual variation in spatial reference memory influences cache site choice in a wild bird.

Abstract

The spatial cognitive abilities of food-storing birds are well documented, but how individual variation in spatial memory influences natural caching behaviour is poorly understood. Here we tested wild toutouwai (Petroica longipes) on two spatial memory tasks and compared their performance with caching decisions. We found that birds with better performance on a spatial reference memory task also travelled further to cache food items. As widely distributed caches are thought to offer protection against cache theft, birds with better reference memories may therefore gain greater benefits from food-storage than birds with poor memories. Females outperformed males in the spatial reference memory task, and performance also declined with age. Birds also displayed marked individual differences in how they interacted with the reference memory task, with some potentially following a heuristic to locate the reward. By contrast, birds showed no evidence that they learned the contingencies of a working memory task. Our results provide empirical evidence that individual variation in spatial memory performance influences the choices that toutouwai make during caching. We recommend that researchers seeking to link cognition and behaviour in the wild take care to select ecologically relevant cognitive tasks that are likely to underpin fitness-linked behaviours targeted by selection.