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Stable hydrogen isotope analysis of bat hair as evidence for seasonal molt and long-distance migration

P.M. Cryan·M.A. Bogan·R. O. Rye·G. P. Landis·C.L. Kester
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Abstract

Although hoary bats ( Lasiurus cinereus ) are presumed to be migratory and capable of long-distance dispersal, traditional marking techniques have failed to provide direct evidence of migratory movements by individuals. We measured the stable hydrogen isotope ratios of bat hair (δD h ) and determined how these values relate to stable hydrogen isotope ratios of precipitation (δD p ). Our results indicate that the major assumptions of stable isotope migration studies hold true for hoary bats and that the methodology provides a viable means of determining their migratory movements. We present evidence that a single annual molt occurs in L. cinereus prior to migration and that there is a strong relationship between δD h and δD p during the molt period. This presumably reflects the incorporation of local δD p into newly grown hair. Furthermore, we present evidence that individual hoary bats are capable of traveling distances in excess of 2,000 km and that hair is grown at a wide range of latitudes and elevations. Stable hydrogen isotope analysis offers a promising new tool for the study of bat migration.

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P.M. Cryan, M.A. Bogan, R. O. Rye, G. P. Landis, C.L. Kester. 2004. Stable hydrogen isotope analysis of bat hair as evidence for seasonal molt and long-distance migration. https://doi.org/10.1644/brg-202

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