Estimating endogenous nutrient allocations to reproduction in Redhead Ducks: a dual isotope approach usingδD andδ¹³C measurements of female and egg tissues.

HOBSON, K. A.; ATWELL, L.; WASSENAAR, L. I.; YERKES, T.

1. Clutch formation represents a considerable energy expense for waterfowl, yet little evidence is available to quantify nutrient allocation from endogenous and exogenous sources. Here we investigated hydrogen and carbon stable isotope ratios (δD andδ13C) in female Redhead Ducks (Aythya americana) and their eggs to evaluate the use ofδD as an indicator of nutrient sources to reproduction.2. Females arrived with mean muscle tissueδD andδ13C values more positive than those of the local food web, reflecting marine dietary inputs from the wintering grounds. These values changed to the range of local food values by late incubation.δ13C values from albumen and yolk protein were correlated, supporting the presence of a common exogenous carbon source for these egg components.3. There was no significant correlation betweenδD orδ13C values in egg tissues and abdominal fat or muscle from the corresponding laying female. No general population-level trends in isotope values from sequentially developing follicle yolks were found.4. Redhead females relied mainly on dietary lipids and proteins for egg production, and therefore endogenous reserves were used to satisfy female body maintenance and energy requirements.Functional Ecology(2004)18, 737–745

DUCKS; BIRD eggs; TISSUES; REPRODUCTION; STABLE isotopes in ecological research; DEUTERIUM

Functional Ecology, 2004, Vol 18, Issue 5, p737

0269-8463

Academic Journal

10.1111/j.0269-8463.2004.00890.x