The sun compass

Abstract

The sun compass was discovered by Kramer (1950) in caged birds showing migratory restlessness. Subsequent experiments with caged birds employing directional training and clock shifts showed that the sun azimuth is used, and the sun altitude ignored. In the laboratory, McDonald found the accuracy to be ±3° to ±5°. Caged birds trained at medium northern latitudes were able to allow for the sun's apparent movement north of the arctic circle, but not in equatorial and trans-equatorial latitudes. In homing experiments, and employing clock shifts, Schmidt-Koenig demonstrated that the sun compass is used by homing pigeon during initial orientation. This is the principal evidence for the existence of a map-and-compass navigational system. Pigeons living in equatorial latitudes utilize the sun compass even under the extreme solar conditions of equinox, achieving angular resolution of c3° in homing experiments. -from Authors