Nut caching by blue jays (Cyanocitta cristata L.): Implications for tree demography

We examined jay caching patterns over 3 yr in a woodland-prairie landscape in 3-central Iowa. Three aspects were examined: jay habitat preferences for caching, jay caching patterns before and after fire, and the influence of predation on nuts by small mammals on tree recruitment in jay territories. Blue jays cached nuts in a wide range of habitats, from open, grassy patches to mature forest. Jays cached preferentially in regenerating woodland and edge habitats while usually avoiding grassland habitats. Caching increased in grassland following a controlled burn. Detection by small mammals of artificial nut caches placed by the investigator was extremely high. The results support a keystone role for blue jays in oak forest ecosystems based on their habit of caching large numbers of most acorn species in the ground in habitats generally suitable for germination and establishment. Their long-distance transport and caching activities would be most significant to tree population dynamics during climate change or in contemporary fragmented landscapes.