Variations in the Reproductive Activities of Arctic Terns at Churchill, Manitoba

Abstract

Nest locations and contents were observed in 16 colonies over a 3-year period. Laying times correlated with spring temperatures, but not with colony size. Clutch size increased with time between ice breakup and laying onset. Egg losses were insufficient to account for differences in clutch size. The results are taken to indicate that under arctic conditions, variations in clutch size, timing of the nesting cycle, and associated events in the Arctic Tern are closely related to variations in the physical environment.