Early Development of Supplementally Fed, Free-Ranging Elk

Early development of cervids has been correlated with juvenile survival and lifetime reproductive success. We investigated the contributions of elk (Cervus elaphus) densities, weather conditions, and supplemental feeding to birth weights, birthdates and weight gains of neonatal elk in northwest Wyoming during 1978-92. Male calves of free-ranging elk were born later (P = 0.01) and weighed more (P <0.03) than females. Annual rates and duration of supplemental feeding had no measurable effect on birth weight of elk calves. Cohort birth weights varied independently of elk densities on winter and summer ranges, but correlated with December and January temperatures (P <0.001) and with the onset of spring greenup (P <0.04). Winter survival and cohort birth weight were correlated for those calves that entered each winter. Nutritional benefits of winter feeding on maternal condition entering late gestation may have improved milk yields of dams thus producing weight gains through the first week of life that exceeded rates of gain previously reported for elk neonates.