Wing Shape Influences Stopover Strategies in a Migratory Shorebird, the Common Snipe

Abstract

The basic assumption in the morphology of avian migrants is that longer, more pointed and concave wings are well adapted for long-distance migratory flights. We investigated how wingtip morphology of the Common Snipe was associated with aspects of its migration, such as amount of accumulated fat, refueling rates, length of stay at the stopover site, and timing of post-juvenile molt. Our study took place at the Jeziorsko reservoir, central Poland, where over 400 first-year Common Snipe (Gallinago gallinago) were caught in 2008 and 2009. Wing shape was found to correlate with different components of the species' stopover strategies. After controlling for the date of capture we found that first-year birds with wings adapted for efficient migration (pointed/concave wingtips) refueled more quickly and stayed for shorter times at the stopover site. Pointed/concave wing shape was also associated with accumulation of smaller fat reserves and later initiation of post-juvenile molt during the period of migration. By contrast, snipe having a wing shape adapted for predator evasion (rounded/convex wingtips) refueled more slowly, remained longer, and accumulated greater amounts of fat, which in turn facilitated earlier molting.