Successful deer management hinges upon a firm understanding of herd dynamics, including highly controversial adult sex ratios. Deer hunters commonly complain about the scarcity of antlered bucks, some claiming areas they hunt often have 10 or more does for every buck. Meanwhile, some biologists contend that sex ratios so heavily skewed to females are rare, and where they do exist, will soon self-correct to no more than two or three adult does per adult buck
From an evolutionary standpoint, researchers generally agree that predation is the primary factor responsible for skewed adult sex ratios among ungulates. If so, they say, then deer harvesting by hunters is a form of predation and equally important in altering whitetail adult sex ratios.
When talking about buck-to-doe ratios, it is generally agreed the topic is adult animals. Adult deer are those that are 1½ years old or older. Trying to dissect the argument any other way is too complicating and even more confusing.
Although buck-to-doe ratios have received a great deal of popular press, the subject has received surprisingly scant attention in the scientific literature.
Most conclusions have been based upon computer models using historical data that is no longer valid. Others have made calculations founded upon erroneous assumptions (i.e., random buck harvesting and stable, high recruitment) or used observational data of questionable value. Controlled studies involving purposeful manipulation of deer sex and age composition, or of nonhunting mortality factors, seem nonexistent.
Clearly, adequate annual recruitment is the ultimate factor governing maintenance of balanced adult deer sex ratios, given current practices that encourage heavy buck harvesting. Stable recruitment rates of better than 1 fawn per doe, reared to yearling age, assures closely balanced adult sex ratios, regardless of hunting strategy.
John Ozoga is Deer & Deer Hunting’s deer research editor.
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