Inferring the ecology of willow warblers during their winter moult by sequential stable isotope analyses of remiges
We present a comparison of feather stable isotope (C-13, N-15) patterns representing the habitat and diet conditions for two subspecies of willow warblers Phylloscopus trochilus that breed in parapatry, but winter in different regions of sub-Saharan Africa. Previous analyses have shown that on average winter moulted innermost primaries (P1) show subspecific differences in N-15 values, although ind