Seasonal variation in the orientation of homing pigeons: new evidence for a latency in the sun compass

Homing pigeons must keep track of the seasonal variations in the sun's daily motion to use the sun as a reference. A delay of seven weeks in such updating of their ephemerides was previously interpreted as being the cause of the behavior of control pigeons studied near the equator in September, when birds released in the morning flew anomalously to the right of birds released in the afternoon. Demonstration of the chronic existence of a delay was obtained by observing that the anomaly was still present but inverted in sign in March, when the pigeons released in the morning flew to the left of those released in the afternoon