Hippocampal volume does not change seasonally in a non food-storing songbird

Seasonal differences in hippocampal morphology have been reported in food-s toring birds. Non food-storing species have not been investigated however. It is therefore unclear whether seasonal changes in the hippocampus are spe cifically related to food-storing or reflect a more general seasonal mechan ism that occurs in both food-storing and non food-storing birds alike. We d etermined the volumes of the hippocampal formation and remaining telencepha lon in the non-storing male song sparrow (Melospiza melodies morphna) in tw o experiments comparing birds collected in the spring and fall of 1992-94 ( Experiment I) and 1997 (Experiment 2). Although pronounced seasonal changes in song control nuclei such as the HVC and RA were previously reported for the same brains used in Experiment I, we found that hippocampal volume did not change with season in either Experiment 1 or 2 for these song sparrow brains. These results suggest that seasonal changes in the hippocampus do n ot occur in this non food-storing species and may be specific to food-stori ng birds. NeuroReport 12:1925-1928 (C) 2001 Lippincott Williams & Wilkins.