Isotope record tracks changes in historical wintering ranges of a passerine in sub-Saharan Africa

Abstract

Billions of birds migrate from the Palaearctic to sub-Saharan Africa, yet we are unaware about where exactly they stay over winter and how consistent they have been using these wintering areas over historical times. Here, we inferred the historical wintering areas of Eurasian Golden Orioles (Oriolus oriolus) from stable isotope ratios of feathers. Over the past 200 years, Golden Orioles used two major wintering grounds. Between 1895 and 1971, the relative use of these areas depended on local rainfall intensities. Golden Orioles may depend strongly on humid wintering areas in sub-Saharan Africa, which may put this species at stake when the global climate continues to change.