Survival in wood duck broods

Mortality of wood ducklings (Aix sponsa) from hatching to 6 weeks of age averaged 47 percent during a 4-year study at the Patuxent Wildlife Research Center. Over 90 percent of the total mortality occurred during the first 2 weeks of life. Brood bonds began to dissolve after the fifth week. hlortality after 2 weeks was so low that Class I1 broods were believed to provide reliable estimates of production to flying age. Once-a-week brood censuses proved unreliable in estimating survival, but twice-a-xveek counts were accurate enough to estimate total broods and survival to Class II age.