Figure 1.

The avian sun compass is time compensated and takes into consideration the movement of the Sun across the sky during the day. Animals using such a time-compensated sun compass need to compensate for the azimuthal change of the Sun over the day when determining their goal direction (dark arrow). The example shows three sun positions over a day (sunrise in pink, noon in yellow and sunset in orange) and the changing relationships (angles in respective colours) between sun position and the goal direction. In order to be able to determine this angle correctly, the animals needs to be able to precisely measure local time. gN, geographical north.