期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：12
页码：8096-8100
DOI：10.1073/pnas.082240899
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Stable isotope analysis is widely promoted as a practical method for tracing the geographic origins of migratory birds. However, the extent to which geospatial patterns of isotope ratios in avian tissues are influenced by age-specific, altitudinal, and temporal factors remains largely unexplored. We measured carbon (13C/12C) and nitrogen (15N/14N) isotope ratios in feathers of black-throated blue warblers (Dendroica caerulescens) breeding along a relatively steep altitudinal gradient in the Appalachian Mountains to evaluate the effects of altitude and year on the isotopic signatures of yearling (first breeding season) and older males (>2 years). Breeding males (n = 302) collected during 7 consecutive years exhibited significant age-specific and altitudinal effects in {delta}13C values and age-specific and temporal effects in {delta}15N values. The {delta}13C values of older males increased with altitude at the rate of {approx}1.3{per thousand} per 1,000 m, suggesting a high degree of year-to-year philopatry to narrow altitudinal zones, if not to breeding territories. In contrast, absence of altitudinal patterns in yearlings most likely reflects natal dispersal. Carbon isotope variation ({delta}13C = -26.07 to -20.86{per thousand}) observed along a single altitudinal transect (755 m) nearly brackets the range of {delta}13C values recorded in feathers across the North American breeding range of the warbler from Georgia to New Brunswick (11{degrees} of latitude) and from New Brunswick to Michigan (22{degrees} of longitude). These data indicate that age-specific and altitudinal effects must be considered when using {delta}13C values to delineate the geographic origin of avian species with large altitudinal and latitudinal ranges.
