NUT CACHING BY BLUE JAYS (CYANOCITTA-CRISTATA L.) - IMPLICATIONS FOR TREE DEMOGRAPHY

We examined jay caching patterns over 3 yr in a woodland-prairie lands cape in 3-central Iowa. Three aspects were examined: jay habitat prefe rences for caching, jay caching patterns before and after fire, and th e 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 preferentiall y in regenerating woodland and edge habitats while usually avoiding gr assland habitats. Caching increased in grassland following a controlle d burn. Detection by small mammals of artificial nut caches placed by the investigator was extremely high. The results support a keystone ro le for blue jays in oak forest ecosystems based on their habit of cach ing large numbers of most acorn species in the ground in habitats gene rally suitable for germination and establishment. Their long-distance transport and caching activities would be most significant to tree pop ulation dynamics during climate change or in contemporary fragmented l andscapes.