Discrimination Factors for Stable Isotopes of Carbon and Nitrogen in Blood and Feathers from Chicks and Juveniles of the California Condor

[摘要] Abstract. Stable-isotope ratios of carbon (13C/12C; δ13C) and nitrogen (15N/14N; δ15N) in animal tissues are analyzed to estimate animal foraging ecology because these ratios reflect those of an animal's diet. This reflection is generally indirect, as stable-isotope ratios change with trophic level. These differences, called discrimination factors (reported as Δ), vary considerably by species and tissue. Variations in discrimination factors used in stableisotope mixing models can lead to inaccurate estimates of diets. Therefore, determining accurate discrimination factors specific to species and tissue is important. We established the Δ13C and Δ15N values between diet and blood and feathers from chicks and juveniles of the California Condor (Gymnogyps californianus). Hatchlings were fed rats for 76–119 days, whereas juveniles were fed dairy calves for 64 days. The mean Δ13C and Δ15N values (± SD) between chick feathers and rat muscle were 0.4 ± 0.4‰ and 3.1 ± 0.2‰, respectively; those between chicks' whol...

[学科分类] 动物科学

[关键词] vulture;fractionation;isotope enrichment;captive-feeding experiment;stable-isotope analysis