SEASONAL-VARIATION IN HIPPOCAMPAL VOLUME IN A FOOD-STORING BIRD, THE BLACK-CAPPED CHICKADEE

Black-capped chickadees (Faults atricapillus) in upstate New York show a peak in food-hoarding intensity in October. We caught chickadees at six different times of the year and measured the volume of several br ain structures. We found that the hippocampal formation, which is invo lved in spatial memory for cached food items, has a larger volume, rel ative to the rest of the brain, in October than at any other time of t he year. We conclude that there is an association between the intensit y of food hoarding and the volume of the hippocampal formation and sug gest that the enhanced anatomy might be caused by the increased use of spatial memory. (C) 1995 John Wiley and Sons, Inc.