Natality of black-tailed deer in McDonald State Forest

Graduation date: 1973Natality of black-tailed deer in McDonald State Forest was determined by examination of 147 reproductive tracts. Yearlings collected from November of 1968 to May of 1970 had an average of 0.79 corpora lutea per doe, and adults 1.76 corpora lutea per doe. Yearlings collected during the spring in 1969 and 1970 had an average of 0.88 fetuses per doe and adults an average of 1.61 fetuses per doe. No fawn had either a fetus or a corpus luteum. The peak of breeding as established from ovarian examination in the fall occurred from\ud November 1 to November 16 during both years of study. Deer collected after a severe winter in 1968-1969 had an index of condition based on kidney fat significantly lower than after the winter of 1969-1970. The rate of ovulation and number of fetuses per doe during the more severe winter were lower than during the milder\ud winter, but the differences were not statistically significant. Frequency of dates on which female black-tailed deer apparently bred in 1969 and 1970 as established by estimating the duration of embryonic development and counting backwards from the date the deer was collected differed between 1969 and 1970. Examination of ovaries collected in October and November established that there was no difference between years in the timing of ovulation. The difference was believed due to the reduced condition of the does and resulting reduced growth of fetuses following the severe winter of 1968-1969. Information from life tables constructed by determining age of animals harvested by hunters revealed a population slightly above the point of optimum yield