DIFFERENCES IN HIPPOCAMPAL VOLUME AMONG FOOD STORING CORVIDS

The hippocampal complex (hippocampus and parahippocampalis) is known t o play a role in spatial memory in birds and is known to be larger in food-storing versus non-storing birds. In the present study, we invest igated the relative volume of the hippocampal complex in four food-sto ring corvids: gray-breasted jays (Aphelocoma ultramarina), scrub jays (Aphelocoma coerulescens), pinyon jays (Gymnorhinus cyanocephalus), an d Clark's nutcrackers (Nucifraga columbiana). The results show that Cl ark's nutcrackers have a larger hippocampal complex, relative to both body and total brain size, than the other three species. Clark's nutcr ackers rely more extensively on stored food in the wild than the other three species. Clark's nutcrackers also perform better during cache r ecovery and operant tests of spatial memory than scrub jays. Thus, gre ater hippocampal volume is associated with better performance in labor atory tests of spatial memory and with stronger dependence on food sto res in the wild.