Journal Article

Within-Site Variation in Feather Stable Hydrogen Isotope (δ2Hf) Values of Boreal Songbirds: Implications for Assignment to Molt Origin

Foster, Kenneth R, Godwin, Christine M, Krikun, Richard, Hobson, Keith A, Sólymos, Péter, Bayne, Erin M, Haché, Samuel, Pyle, Peter, Nordell, Cameron J

2016

نظرة عامة

Understanding bird migration and dispersal is important to inform full life-cycle conservation planning. Stable hydrogen isotope ratios from feathers (δ2Hf) can be linked to amount-weighted long-term, growing season precipitation δ2H (δ2Hp) surfaces to create δ2Hf isoscapes for assignment to molt origin. However, transfer functions linking δ2Hp with δ2Hf are influenced by physiological and environmental processes. A better understanding of the causes and consequences of variation in δ2Hf values among individuals and species will improve the predictive ability of geographic assignment tests. We tested for effects of species, land cover, forage substrate, nest substrate, diet composition, body mass, sex, and phylogenetic relatedness on δ2Hf from individuals at least two years old of 21 songbird species captured during the same breeding season at a site in northeastern Alberta, Canada. For four species, we also tested for a year × species interaction effect on δ2Hf. A model including species as single predictor received the most support (AIC weight = 0.74) in explaining variation in δ2Hf. A species-specific variance parameter was part of all best-ranked models, suggesting variation in δ2Hf was not consistent among species. The second best-ranked model included a forage substrate × diet interaction term (AIC weight = 0.16). There was a significant year × species interaction effect on δ2Hf suggesting that interspecific differences in δ2Hf can differ among years. Our results suggest that within- and among-year interspecific variation in δ2Hf is the most important source of variance typically not being explicitly quantified in geographic assignment tests using non-specific transfer functions to convert δ2Hp into δ2Hf. However, this source of variation is consistent with the range of variation from the transfer functions most commonly being propagated in assignment tests of geographic origins for passerines breeding in North America.

• الناشر: Public Library of Science,Public Library of Science (PLoS)
• موضوع: Animal feathers / Biology and Life Sciences / Bird migration / Birds / Body mass / Breeding / Breeding seasons / Climate change / Computer and Information Sciences / Connectivity / Conservation / Dispersal / Ecology / Feathers / Forage / Forages / Growing season / Hydrogen / Hydrogen isotopes / Interspecific / Isotope ratios / Land cover / Land use / Medicine and Health Sciences / Migratory birds / Molting / Oil sands / Ornithology / Phylogenetics / Phylogeny / Physiological aspects / Precipitation / Precipitation (Meteorology) / Protection and preservation / Research and Analysis Methods / Songbirds / Species / Studies / Substrates / Transfer functions / Variation