Frequency distribution of conception dates in a white-tailed deer herd

Abstract

Conception dates of white-tailed deer, Odocoileus virginianus (Zimmermann, 1780) were estimated for the breeding periods of 1974-76 and 1984 using fall and winter - spring fetal data. Conception dates estimated from data collected in the fall were biased. This bias resulted in an earlier mean conception date than that based on information which included data from later breeding females. Mean breeding dates differed significantly between female age classes due to delayed conception in fawns which also resulted in a skewed frequency distribution of conception dates. The frequency distribution of conception dates was leptokurtotic, suggesting that the distribution is constrained in time by some factor(s). Conception date estimates did not differ by habitat type but were influenced significantly by period of data collection. Mean breeding date for deer on the Savannah River Site, corrected for age class sampling bias, is 20 November +/- 27 days (adults plus fawns) and 13 November +/- 15 days (only adults).