Spatial patterns of the isotopic composition of bird feathers and their implications

Abstract

Studying isotopic composition of bird feathers is an emerging field. It can yield important information regarding diet and provenance of the birds. In this study we have carried stable isotopic analysis for the feather museum samples. These samples are obtained from all over the India by BNHS. In this study δ15N feather values were dependent on tropic level. δ13C feather values were determined by C3 & C4 proportion in diet of the birds. δ34S values were dependent on underlying geology of the place but also showed some dependence on diet. Seabird species used showed enriched δ34S and δ15N values and this can be used to distinguish between marine diet and terrestrial diet. δ18O and δ34S of bird feathers appears to have a spatial control and hence could be useful in studying migration of birds in the Indian context. We have demonstrated here that the birds from different geographical regions/biomes in India have distinct isotopic signatures. Baseline data created in the present study will form basis to study migration of birds in India.