In 1492, Columbus encountered frigate birds while en route to the New World and noted that the bird “does not alight on the sea nor depart from land 20 leagues” (1). Columbus observed correctly that frigate birds do not land on the sea, but he severely underestimated how far some frigate birds fly from land. On page 74 of this issue, Weimerskirch et al. (2) show that great frigate birds (Fregata minor) reduce transit costs by riding strong thermal updrafts beneath or inside cumulus clouds and then gliding long distances to another thermal, searching for food along the way. By exploiting cumulus clouds and trade winds in the Indian Ocean, the birds forage around the doldrums, a largely windless zone.
Authors: Raymond B. Huey, Curtis Deutsch