Nutrient Reserve and Organ Dynamics of Breeding Cinnamon Teal

I examined nutrient and organ dynamics of breeding Cinnamon Teal (Anas cyanoptera) in Arizona to determine when nutrient reserves, if any, were acquired, and the relative use of endogenous and exogenous nutrient sources during clutch production. Females stored lipid and protein after arrival and through rapid follicle growth (RFG). Females expended lipid reserves during laying (P = 0.0001, r2=0.85), but size of remaining lipid reserve was not related to the number of eggs laid (P = 0.22, r2=-0.10), nor to the estimated amount of lipid needed to complete the clutch in laying females (P = 0.54, r2=-0.04). Females did not use endogenous protein during laying (P = 0.12, r2=0.10). Males stored protein while their mates underwent RFG. Digestive organ measures in both sexes varied in relation to feeding ecology during breeding. Small body size, the ability to exploit a diversity of foods, and time constraints on nutrient acquisition likely influence nutrient reserve dynamics of breeding Cinnamon Teal in Arizona.