The homing pigeon hippocampus and the development of landmark navigation.

The role of the homing pigeon hippocampal formation was examined in the development of loft fidelity and landmark navigation. During the course of five summers, different groups of young pigeons (hippocampal-lesioned, control-lesioned, and unoperated controls) were given free flight experience followed by short distance training and experimental releases. In Experiment 1, a census of which loft each pigeon entered revealed that hippocampal lesioned pigeons displayed less loft fidelity than controls. In Experiment 2 and 3, the percent of young birds lost during their first summer of training and their first experimental release was examined. Despite displaying similarly good homeward-oriented vanishing bearings, significantly more hippocampal lesioned pigeons were lost compared to control groups. The results support the hypothesis that the homing pigeon hippocampal formation participates in the learning/operation of a spatial representation of local landmarks near the loft that can be used for loft recognition and navigation.