Body reserves of neonate northern pintails (Anas acuta)

Abstract

Neonate northern pintails (Anas acuta) had a high lipid content primarily attributable to the fat deposits in their carcasses. Their yolk sacs contained 24% of the total lipid at hatching. In the absence of food, newly hatched northern pintails survived by catabolizing their carcass fats. The yolk sac was not an important source of endogenous nutriment under starvation conditions but appeared to be important to the growth of ducklings, contributing materials for the synthesis of nonfat tissue. The function of yolk sacs is reviewed and the body composition of neonate northern pintails is compared with that of other species in relation to the developmental maturity of the young.