Temporal and spatial pattern of common tern (Sterna hirundo) foraging in the Wadden Sea.

In 1989, 313 foraging flights of common terns in the Wadden Sea were radio-tracked. The feeding trips lasted on average 115 min covering about 30 km per flight. Completely tracked flights had a mean radius of 6.3 km. The terns preferred distinct foraging areas in the Wadden Sea. These were visited at site-specific phases of the tidal cycle resulting in a temporal and spatial pattern of foraging, caused by the site-specific and tide-related fluctuations of food availability.