Factors that influence assimilation rates and fractionation of nitrogen and carbon stable isotopes in avian blood and feathers

Stuart Bearhop*, Susan Waldron, Stephen C. Votier, Robert W. Furness

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

489 Citations (Scopus)

Abstract

By switching great skuas Catharacta skua from one isotopically distinct diet to another, we measured diet-tissue discrimination factors and tested the assumption that dietary nitrogen and carbon isotope signatures are incorporated into blood and feathers at similar rates. We also examined the effects of metabolic rate and looked for evidence of isotopic routing. We found that blood δ15N and δ13C signatures altered after the diet switch at similar rates (14.4 d and 15.7 d, respectively). Qualitative analyses imply that the same was true with feathers. Mass balance calculations suggest that only a small amount of lipid is likely to be involved in the synthesis of blood and feathers. Differences in diet-tissue discrimination factors before and after the diet switch may mean that toward the end of the experiment, some of the nutrients for blood synthesis had been coming from stores. Repeated measures mixed models provided evidence that increases in metabolic rate might accelerate fractional turnover rates in blood. There is a need for more laboratory-based experimental isotope studies in order to address further questions that this study has raised.

Original languageEnglish
Pages (from-to)451-458
Number of pages8
JournalPhysiological and Biochemical Zoology
Volume75
Issue number5
DOIs
Publication statusPublished - Sept 2002

ASJC Scopus subject areas

  • Physiology
  • Biochemistry
  • Animal Science and Zoology

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