RELATIONSHIP BETWEEN WATERFOWL NUTRITION AND CONDITION ON AGRICULTURAL DRAINWATER PONDS IN THE TULARE BASIN, CALIFORNIA - WATERFOWL BODY-COMPOSITION

We examined carcass composition and proximate food composition of rudd y ducks (Oxyura jamaicensis), northern shovelers (Anas clypeata), and northern pintails (Anas acuta) wintering on agricultural drainwater po nds in California during 1983-84. Lipids varied seasonally in northern shovelers and northern pintails. Protein did not fluctuate except in ruddy ducks whose protein mass increased over winter, suggesting that some protein was catabolized prior to arrival on wintering areas or th at a buildup of protein occurred prior to spring migration. Waterfowl diets varied among species and time, but the nutritional composition o f the diets was relatively stable. Ruddy ducks and shovelers consumed mostly animal foods rich in protein (53-60%) and low in Nitrogen Free Extract (NFE)(1-7%). Pintail diets contained more NFE (23-38%) and les s protein (14-38%) because of greater consumption of plant foods. Nutr itional composition of pintail diets varied with lower protein consump tion occurring from November through January.