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Predator avoidance may further be responsible for use of steep slopes or proximity to escape cover. As offspring become older and better able to escape predators, behavior and patterns of habitat use might be expected to change. “During winter, protection of offspring might be of less concern than satisfying dietary needs because of the reproductive trade-off between caring for present young and future offspring. Results from studies of winter diets suggest females feed more selectively than males, presumably because of their smaller size and the protein requirements of gestation.

Equally unfortunate is that seasonal differences in food, cover and social requirements of the two sexes are seldom considered in deer-management plans. Given the potential significance of those differences, some of us researchers question whether current deer habitat and herd-management strategies adequately serve both sexes. Are we more often bound to systems that strive to produce an abundance — and sometimes an overabundance — of whitetails for political reasons, regardless of the herd’s condition?

Two techniques sometimes used in reproductive studies involve laparoscopy and laparotomy, which both require minor surgery. An incision is made in the abdominal area to insert an instrument called an endoscope, which allows a visual examination of the ovaries and uterus. At Michigan’s Cusino Wildlife Research Station in the early 1960s, we developed X-ray procedures to determine pregnancy in live deer. Although we routinely X-rayed female deer as part of our studies, I’m unaware of many other uses for this technique in deer research.