Migratory birds can use celestial and magnetic cues to locate their migratory direction.
The relative importance of the two cue systems was analyzed by testing Australian Silvereyes for their orientation behavior in a cue-conflict situation during spring at dusk. Control birds tested under the natural sky in the local geomagnetic field headed in their southerly migratory direction. Subsequently, all birds were tested under the sky in the absence of magnetic information. Both groups continued in their previous direction, control birds south and experimental birds northeast, by celestial cues alone. Tested indoors with the magnetic field as the only cue, both groups headed southward.