Flight speeds of swifts (Apus apus): seasonal differences smaller than expected.

ABSTRACT: We have studied the nocturnal flight behaviour of the common swift (Apus apus L.), by the use of a tracking radar. Birds were tracked from Lund University in southern Sweden during spring migration, summer roosting flights and autumn migration. Flight speeds were compared with predictions from flight mechanical and optimal migration theories. During spring, flight speeds were predicted to be higher than during both summer and autumn due to time restriction. In such cases, birds fly at a flight speed that maximizes the overall speed of migration. For summer roosting flights, speeds were predicted to be lower than during both spring and autumn since the predicted flight speed is the minimum power speed that involves the lowest energy consumption per unit time. During autumn, we expected flig

SUBMITTER: Henningsson P 

PROVIDER: S-EPMC2690467 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature