a method for investigating population declines of migratory birds using stable isotopes origins of harvested lesser scaup in north america方法调查人口下降的候鸟使用稳定同位素收获较小的起源在北美斑背潜鸭.pdfVIP

A Method for Investigating Population Declines of Migratory Birds Using Stable Isotopes: Origins of Harvested Lesser Scaup in North America 1 2 1 1 Keith A. Hobson *, Michael B. Wunder , Steven L. Van Wilgenburg , Robert G. Clark , Leonard I. Wassenaar1 1 Environment Canada, Saskatoon, Saskatchewan, Canada, 2 Department of Integrative Biology, University of Colorado Denver, Denver, Colorado, United States of America Abstract Background: Elucidating geographic locations from where migratory birds are recruited into adult breeding populations is a fundamental but largely elusive goal in conservation biology. This is especially true for species that breed in remote northern areas where field-based demographic assessments are logistically challenging. Methodology/Findings: Here we used hydrogen isotopes (dD) to determine natal origins of migrating hatch-year lesser scaup (Aythya affinis) harvested by hunters in the United States from all North American flyways during the hunting seasons of 1999–2000 (n = 412) and 2000–2001 (n = 455). We combined geospatial, observational, and analytical data sources, including known scaup breeding range, dD values of feathers from juveniles at natal sites, models of dD for growing-season precipitation, and scaup band-recovery data to generate probabilistic natal origin landscapes for individual scaup. We then used Monte Carlo integration to model assignment uncertainty from among individual dD variance estimates from birds of known molt origin and also from band-return data summarized at the flyway level. We compared the distribution of scaup natal origin with the distribution of breeding population counts obtained from systematic long-term surveys. Conclusions/Significance: O