Sun compass and wind drift compensation in migrating butterflies

Migrating pierid butterflies use a sun compass in order to head in a prefer red flight direction. When blown off-course by the wind, butterflies adjust their heading to compensate for cross-track wind drift. They are capable o f drift compensation over water when and where landmarks are visible on the shore. They are also capable of a more inaccurate form of drift compensati on over the sea when and where landmarks are not visible.