Discriminative basis for astronavigaiton in birds.

Abstract

Matthews has suggested that birds use sun navigation to obtain their orientation. He hypothesized that the bird assesses the sun''s arc and uses the altitude of the highest point to obtain its latitude, and changes in the arc angle (together with a sense of time), to estimate its longitude. This study investigated birds'' ability to discriminate these dimensions and concluded that homing pigeons are able to detect movement at 15[degree] an hour, and can discriminate changes in altitude and changes in arc angle. The level of discriminated changes of altitude and arc angle would not support pinpoint navigation, but the study provides data compatible with Matthews'' theory.