Management plans to improve deer herd health or increase the average white-tail buck body size and antler dimensions on a tract of land generally include reducing doe numbers as an objective. However, beginning deer managers seldom realize the significant effort required to accomplish this objective. I analyzed data we had available from The Noble Research Institute's Wildlife Unit and Coffey Ranch to provide some insight concerning this activity.
When the Foundation purchased the Wildlife Unit in 1981, does were virtually unhunted. Doe-only hunting was initiated in 1982, and continued through 1984. Doe harvest with guns averaged 0.63 does/100 acres over the three years. Doe hunting efficiency is illustrated in the graph below. Hunter days (defined as one hunter hunting any part of a day) per harvested doe climbed from 2.7 to 6.7 over the three years. This trend illustrates a common phenomenon; as harvest pressure is applied to does, survivors become increasingly difficult to remove from the same tract of land.
The Noble Research Institute's Coffey Ranch began participation in the Oklahoma Department of Wildlife Conservation's Deer Management Assistance Program (DMAP) in 1992, which allows doe harvest every day of every deer season. I calculated their doe hunting efficiency by season in terms of the number of hunts per doe, with a hunt defined as a morning, mid-day, or evening effort. These results are depicted in the graph.
Annual doe harvest averaged 0.39 does/100 acres over the 1992-1997 period. As expected, archery hunting was the least efficient, muzzleloader hunting was intermediate, and rifle hunting was the most efficient, averaging 50.9, 12.8 and 9.4 hunts/doe, respectively, over the six-year period. This data does not show decreasing doe harvest efficiency over time for two reasons.
First, some doe harvest had been applied on the ranch since 1987 and so survivors were already educated at the beginning of this period. Second, doe harvest intensity was much less than that applied in the Wildlife Unit example.
So what do all these numbers mean? Perhaps an example would be helpful. Let's say we have a 3,000-acre ranch, and our doe harvest objective is one doe/100 acres or 30 does (reasonable for our area). If we assume most does will be killed in rifle season (in Texas) or rifle and primitive seasons (in Oklahoma), we might project a 10 hunts/doe harvest efficiency. This would require 300 hunts (!), or an average of five hunts per day over a 60-day season (Texas), or 17 hunts per day over each of two nine-day seasons (Oklahoma DMAP-participating ranches). Actually, this rate probably underestimates the effort necessary because does become more difficult to harvest as the harvest objective is approached.
Most inexperienced deer managers envision doe reduction as a simple task. However, as these numbers illustrate, effective doe harvest requires an intensive effort, and it becomes more difficult over time. If we can help you with management plans for the upcoming deer season, give us a call.