The Research 
The ACL was designed by Drs. Russell Balda and Alan Kamil to conduct experiments on spatial cognition in seed caching birds of the family Corvidae.  Field work was initiated on this topic in the late 1960's with studies on the local birds including Clark’s nutcracker, pinyon jay and western scrub-jay. Initial laboratory studies were designed to explore the spatial memory of the Clark’s nutcracker.  An individual of this species can cache up to 33,000 pine seeds in thousands of subterranean sites and return up to 13 months later to recover these seeds with errorless accuracy.  This bird might well have the best spatial memory of all vertebrates, including humans. 

Photograph of cache site by R. Seebrasse

Subsequent experiments were designed to test for species differences in spatial memory among members of the jay family that have different natural histories and ecologies, and different degrees of reliance on pine seeds.  Some species store fewer seeds, live in habitats that are not so demanding, and recover seeds at a slower rate.  We asked the question, “Do species with less dependence on the buried seeds for overwinter survival and early reproduction have less accurate spatial memory than those species with greater dependence on their cached seeds?” The answer appears to be yes.   This implies that the brain has become more specialized for spatial memory in some species, and less specialized in others.  This work has become central to investigating the adaptive specialization hypothesis.  This hypothesis states that selective forces have shaped the brains of these species differently as adaptations to different environmental conditions.

Recently, work in the lab has focused on the social complexity hypothesis, which was proposed by ACL researchers for birds in a 1996 publication.  The social complexity hypothesis suggests that animals that live in complex social units must have mental capabilities that help them resolve problems encountered in their social group.  The more complex the social group, the greater the need for social cognitive abilities. To date, two groups of experiments, the most recent published in Nature, have provided support for this hypothesis.  Although this hypothesis was first proposed for primates (Seyfarth and Cheney 1990), no experimental evidence has been found for it in primates.  Researchers at the ACL, in coordination with researchers at the University of Nebraska’s Center for Avian Cognition, are the first and only group to present evidence in favor of this hypothesis.

Research at the ACL has been generously supported by grants from the National Science Foundation and the National Institute of Mental Health.  The ACL’s research program received national recognition when it was listed as one of the five top research programs in animal behavior supported by NSF, and being featured in the Think Tank exposition at the U.S. National Zoo.  Balda and Kamil also received the Brewster Memorial Award for lifetime achievement from the American Ornithologist’s Union at its annual meeting in 2004.

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