The Physical Basis of Astro-Navigation in Birds: Theoretical Considerations

Abstract

ABSTRACT Matthews’s hypothesis of sun navigation in its original form is rejected on the grounds of physical impossibility of making one of the measurements, and an invalid assumption in the reasoning. It is suggested that the bird should measure the sun’s altitude and rate of change of altitude. The position lines corresponding to these quantities are discussed, and the way in which birds might make and use such observations is considered. The sensory performance required is shown to be reasonable. The magnitude and direction of the errors of position resulting from various sorts of errors of observation are discussed in relation to the experimental evidence. Suggestions are put forward for future experiments.