Stable isotope ratios in winter-grown feathers of Great Reed Warblers Acrocephalus arundinaceus, Clamorous Reed Warblers A. stentoreus and their hybrids in a sympatric breeding population in Kazakhstan
Analyses of the stable isotope composition of feathers can provide significant insight into the spatial structure of bird migration. We collected feathers from Great Reed Warblers Acrocephalus arundinaceus, Clamorous Reed Warblers A. stentoreus and a small sample of their hybrids in a sympatric breeding population in Kazakhstan to assess natural variation in stable isotope signatures and delineate