Stable hydrogen isotopes identify leapfrog migration, degree of connectivity, and summer distribution of Golden Eagles in eastern North America

Abstract

ABSTRACT Knowledge of the distribution and movements of populations of migratory birds is useful for the effective conservation and management of biodiversity. However, such information is often unavailable because of the difficulty of tracking sufficient numbers of individuals. We used more easily obtained feather stable hydrogen isotope ratios (δ2H) to predict the summer grounds of the small, threatened, and migratory population of Golden Eagles (Aquila chrysaetos) in eastern North America. We then identified summer locations and the extent of migratory connectivity for this population. We collected δ2H (δ2Hf), stable carbon isotope (δ13C), and stable nitrogen isotope (δ15N) data from the body feathers of 47 juvenile, subadult, and adult Golden Eagles. Values of δ13C and δ15N suggested that all but 2 birds obtained food from terrestrial-based food webs and therefore that δ2H data were appropriate for inferring the geographic region of molt for the majority of birds. There was relatively large interfeath...