Spring migration decisions in relation to weather are predicted by wing morphology among trans-Mediterranean migratory birds

2. We studied the covariation between capture frequencies and meteorological conditions at departure and at a stopover site during northward spring migration in 21 species of migratory birds. The stopover site is a small island located at the northern end of a wide ecological barrier (the Mediterranen Sea), that is crossed with non-stop flights by migrants departing from North Africa.

P>1. Meteorological conditions are critical determinants of bird migration. However, response to weather should vary among species as well as between males and females, as phenotypic traits relevant to migration are also shaped by natural selection acting differentially on species and either sex in other life cycle phases.