Diet-tissue discrimination factors (δ15 N and δ13 C values) for blood components in Magellanic (Spheniscus magellanicus) and southern rockhopper (Eudyptes chrysocome) penguins.

We compare our DTDFs with published values from blood components of penguins and discuss the effects that lipid extraction, sample storage, and diet have on the DTDFs of penguin blood components. This study provides accurate DTDFs of blood components for two seabird species of conservation concern, and is one of the first to provide plasma DTDFs for penguins, which are underrepresented in the seabird literature.