Migration pattern of Yellow-throated buntings revealed by isotope-based geographic assignment

Abstract

ABSTRACTMigratory birds have evolved diverse migration strategies in response to a variety of factors, but information about the detailed migration patterns of Asian songbirds is not yet available. To understand the short-distance migration pattern of declining Yellow-throated Buntings (Emberiza elegans) in East Asia, we analyzed stable isotopes from the outermost tail feathers (rectrices) of individual buntings collected in Korea and Japan. Temporal changes in feather hydrogen (δ2Hf) and oxygen (δ18Of) isotopic values at stopover islands suggested that northern populations start migration earlier than southern populations, especially in autumn. Latitudinal gradient in δ2Hf values of three wintering populations implied that northern breeders wintered farther north than southern breeders. The migration pattern of this bunting, known as Type II chain migration, was also inferred from hydrogen isotope-based geographic assignments of feather growth origins. Our data demonstrate that stable isotope analysis may help to bridge current knowledge gaps in songbird migration despite coarsely mapped isoscapes and as-of-yet undetermined isotope calibration functions in Asia.