A deer management association is a group of land managers in a region who share common deer management goals and make a decision to cooperatively manage their shared deer herd. Attainment of individual landowners' deer management goals is often limited by the number of acres owned compared to home ranges of white-tailed deer. Most landowners do not own property large enough to achieve many deer population goals. Goals such as improving the buck:doe ratio, buck age structure, fawn crop or altering deer density can be more quickly achieved by a group of managers of contiguous land working cooperatively than by relatively small landowners working alone.
The Walnut Bayou Deer Management Association (WBDMA) is comprised of 12,640 acres located along the Red River predominantly in Love County, Okla., with one tract in Cooke County, Texas. Love and Cooke counties are within the Cross Timbers vegetational area, where native woody vegetation is comprised of post oak-blackjack oak forest on uplands and oak-hickory-elm-ash-hackberry forest in the bottoms. In their native condition, openings are dominated by tallgrass prairie species. Much of these openings and some cleared areas have been planted to introduced forages, primarily bermudagrass, and much of the bottomlands are planted annually to cool-season forages.
One of the participating WBDMA properties, the Noble Research Institute's D. Joyce Coffey Ranch, has been under a deer management plan and has leased hunting rights since 1987. The lessees are not allowed to harvest yearling bucks in an effort to increase the age structure of bucks. In time, the lessees began to express concerns about gunshots they were hearing on neighboring property, thinking that the yearling bucks they were not allowed to harvest were being shot by neighboring hunters.
Kent Shankles, Coffey Ranch farm manager, knew all of the neighbors. He visited with each one of them about the concerns expressed by the Coffey Ranch lessees. As it turned out, they shared the same concerns, only they thought yearling bucks were being harvested on the Coffey Ranch and other neighbors' places.
With this information, Shankles proposed a meeting between all neighbors with adjoining properties to the Coffey Ranch and the Noble Research Institute Red River Demonstration and Research Farm (RRDRF) in the spring of 1996. The result was the formation of the WBDMA.
Goals adopted by the WBDMA are as follows:
Deer herd parameters on the WBDMA are estimated through the use of spotlight surveys (Table 1). Five replicates of each line are surveyed between August 15 and September 30 annually. Two points should be made before interpreting the data in the table and figures. At best, spotlight surveys only provide an index of the actual deer population; they are not a census of the deer herd. Second, additional survey lines and additional acreage were added every year as the WBDMA grew.
Estimated buck numbers have more than doubled since 1996 (Figure 1). Harvest (light shade on bar in Figure 1) has averaged 14 percent of the estimated number of bucks since 1996. Bottom line after the 2003 harvest, 197 bucks (one per 64 acres) are given the chance to grow older, which increases average antler size.
Deer numbers on the WBDMA are in excess of what would provide maximum deer growth and size with the existing habitat. Doe harvest information is kept in order to monitor our success in achieving our goal of balancing deer numbers with habitat carrying capacity. Although overall estimated doe numbers have increased since 1996 (Figure 2), they have remained fairly constant since 2000. Harvest (light shade on bar in Figure 2) numbers have averaged 20 percent of the estimated number of does since 1996. Bottom line despite a fairly significant annual harvest, doe numbers remain stable or are increasing slightly.
Adult and yearling doe body weights remained fairly stable from 1996 to 1999. However, body weights declined during 1999-2001, probably due to drought, but appear to be recovering since 2001 (Figure 3).
Another measure of our doe harvest efforts is to look at the percentage of yearling does (1.5 yrs of age) in the annual doe harvest (Figure 4). The percentage of yearling does in the annual harvest seems to have slightly increased since 1996. This is an indication that we are having some impact with our doe harvest. As our overall doe harvest increases, the percentage of yearlings should increase. It will be interesting to see whether the percentage of yearling does in our total doe harvest increases if we can increase our total harvested doe numbers.