ИСТИНА

Female Bar-tailed godwits Limosa lapponica lapponica wintering in the Wadden Sea and breeding in Scandinavia have declined in body size. Body-shrinkage is now seen as a common response to climate change, especially in Arctic animals. With 15 years of capture-resight data we estimated nonlinear bivariate fitness (survival) surfaces for these birds and showed strong directional selection for shortening bill length. Seasonal survival capture-recapture models localized this selection (mortality biased towards the longer billed females) on the wintering grounds in the Wadden Sea rather than the Arctic. With a greater ability to reach deeper-living polychaete worms in the harshest of times, in winter long-billed females have been shown to stay put even during cold snaps. This now turns out the wrong decision when food abundance is low, a strategy now being eliminated by natural selection and reducing body size.