title: Is the western scrub-jay (Aphelocoma californica) really an underdog among food-caching corvids when it comes to hippocampal volume and food caching propensity?
abstract: Food caching has been linked to better performance on spatial memory tasks and enlarged hippocampal volume in both birds and mammals. Within food-caching birds, it has also been predicted that species less reliant on stored food should have inferior spatial memory and a smaller hippocampus compared to species that depend heavily on food caches. Several comparisons suggest that North American corvids have a significantly smaller hippocampus and overall brain volume compared to the Eurasian corvid species and that western scrub-jays (Aphelocoma californica) have a smaller hippocampus compared to the more specialized Clark's nutcracker. Here we present the largest data set of scrub-jay brains and, in contrast to previous reports, show that relative to body mass western scrub-jays have a brain size similar to the largest brain size of Eurasian corvids. The relative hippocampal volume of scrub-jays is also among the largest of all investigated corvids. These findings may not be surprising considering that scrub-jays have been reported to have remarkable cognitive capacities such as episodic-like memory and experience projection. Our data suggest that many previously made assumptions about western scrub-jays as less specialized food hoarders might be an oversimplification and that simple categorization of species into specialized and non-specialized hoarders might not provide useful insights into the evolution of memory and the hippocampus.
authors.affiliation: Department of Biology, University of Nevada Reno, Reno, NV 89557, USA. vpravosu@unr.edu
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Pravosudov
authors.forename: Selvino R
authors.initials: SR
authors.lastname: de Kort
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D046368:Crows; D006624:Hippocampus / Q000033:anatomy & histology / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D013687:Telencephalon / Q000033:anatomy & histology / Q000502:physiology