I examined nutrient and organ dynamics of breeding Cinnamon Teal (Anas
cyanoptera) in Arizona to determine when nutrient reserves, if any, w
ere acquired, and the relative use of endogenous and exogenous nutrien
t sources during clutch production. Females stored lipid and protein a
fter arrival and through rapid follicle growth (RFG). Females expended
lipid reserves during laying (P = 0.0001, r(2) = 0.85), but size of r
emaining lipid reserve was not related to the number of eggs laid (P =
0.22, r(2) = -0.10), nor to the estimated amount of lipid needed to c
omplete the clutch in laying females (P = 0.54, r(2) = -0.04). Females
did not use endogenous protein during laying (P = 0.12, r(2) = 0.10).
Males stored protein while their mates underwent RFG. Digestive organ
measures in both sexes varied in relation to feeding ecology during b
reeding. Small body size, the ability to exploit a diversity of foods,
and time constraints on nutrient acquisition likely influence nutrien
t reserve dynamics of breeding Cinnamon Teal in Arizona.