Food Storage in Gray Jays: Source Type and Cache Dispersion

Animals that store food items in scattered sites must decide how to distribute their caches in space. Our theoretical approach is based on the assumption that such animals disperse their caches in a manner that maximizes the long‐term rate of storage of recoverable (surviving) food items in the habitat. We investigate the cache‐spacing behavior of theoretical scatter hoarders that encounter food sources differing in the energetic content of the items they contain. We then describe a field experiment in which gray jays ( Perisoreus canadensis ) were presented with both small‐ and large‐item food sources. The jays compensated for source type by spacing larger‐item caches more widely, a compensation that would tend to yield a high rate of storage of recoverable food energy over the long term and throughout the territory. Previous models do not adequately account for the observed patterns of cache dispersion.