Terrell County Mule Deer Antler Restriction Results
Following the success of the Panhandle experimental mule deer antler restriction, TPWD initiated the experiment in Terrell County during the 2022 hunting season. Prior to the experiment in Terrell County, TPWD received many requests from landowners, managers, and hunters to improve the buck age structure and sex ratio within the county. Based on local and state surveys the mule deer population had a skewed sex ratio, and an age structure inordinately weighted towards young deer in the buck segment of the population.
Certain types of antler restrictions can be used to successfully reduce the impact of intensive harvest on buck age structure and sex ratios within a population. Therefore, TPWD initiated an experimental antler restriction that prohibited the harvest of any mule deer buck with an outside spread of the main beams that was less than 20 inches. The experimental regulation was designed to reduce excessive hunting pressure on young bucks and shift the age structure of the buck herd toward older age class bucks. By doing so the regulation will help to improve overall hunter and manager satisfaction. Other benefits of managing for a balanced buck age structure include improved sex ratios and shortened breeding periods, which could help to improve fawn recruitment and reduce overall stress on bucks.
The experimental antler restriction began during the 2022 hunting season and will continue for at least two more years. Data will be assessed throughout the experiment, but at the end of 5 hunting seasons, TPWD will propose to either extend, modify, or terminate the experiment. TPWD used a voluntary deer harvest check station at Stuard's Deer Processing in Dryden to collect age and antler measurements during each hunting season. To gather the most harvest data possible, TPWD and their partners offered incentives to hunters who brought their mule deer buck to the check station. Hunters were entered in drawings for items such as a rifle and gift cards. The harvest data collected are essential to effectively evaluate the success of the experimental antler restriction.
Checked Mule Deer Harvest Data
Number of Mule Deer Checked
Only 7 hunters checked their bucks at the voluntary check station in 2022 and 9 in 2023. However, mule deer bucks checked more than doubled with 20 hunters bringing their harvested bucks to the check station in 2024.
Age of Mule Deer Bucks Harvested
Age data prior to the antler restriction (2016-2021; green bars) show that only 33% of the mule deer bucks aged and measured by TPWD biologists were 5.5 years old or older in Terrell County. During the three years of the experiment, 65% of the bucks brought to the check station were 5.5 years old or older. The 2% in the 0.5-2.5-year-old age class represents bucks that did meet the antler restriction minimum. With the antler restriction, a significant reduction in harvested young and middle-aged (0.5-2.5 and 3.5-4.5-year-olds) bucks have been documented, while substantially shifting the harvest to the older age class (5.5-8.5-year-olds).
Mule Deer Sex Ratio
From winter post-season helicopter surveys conducted from 2006-2021 (prior to the experiment), TPWD estimated an average sex ratio of 6.2 does per buck, which is an indicator of intense buck harvest. During the next 3 years of the experimental antler restriction, the average sex ratio was 4.1 does per buck. Substantially more bucks were observed during 2022-2024 helicopter surveys than in years past. The improvement in the sex ratio during 2022-2024 is further evidence that the experiment is having positive population impacts.
Average Age Bucks Checked
In 2021, (the year prior to the initiation of the antler restriction) the average age of mule deer bucks brought to the Terrell County TPWD check station and aged and measured by TPWD biologists was 3.7 years. Currently with the antler restriction in place, the average age of mule deer bucks brought to the Terrell County TPWD check station and aged and measured by TPWD biologists from 2022-2024 has increased to 5.0 years.
Thoughts So Far
Because of severe buck harvest prior to the antler restriction and below average fawn production from drought over the last several years, getting more bucks old enough to meet the antler restriction is going to take some time. But the number of bucks meeting the antler restriction should continue to increase each year until buck numbers naturally stabilize in each age cohort without the additive mortality of buck overharvest.
Preliminary data from Terrell County and information from the Panhandle indicate the antler restriction is not flawless, but all data collected so far point to an undeniable improvement in mule deer sex ratios and buck age structure. These early results demonstrate that the experiment's objectives of managing for a more natural mule deer sex ratio and buck age structure are being met using an outside spread of the main beams antler restriction set at 20”. In addition, public support for the mule deer antler restriction continues to be very favorable. We will continue to evaluate the antler restriction annually for another 2 hunting seasons and encourage all hunters who harvest mule deer bucks within Terrell County to check their deer next season for more great prizes.
Check Station Drawings
As part of the experiment, hunters who brought their harvested mule deer buck from Terrell County to the check station were entered into drawings to win some great prizes thanks to our partners!
Rules and eligibility for drawings:
- Only mule deer bucks harvested within Terrell County were eligible.
- Mule deer must have been brought to a check station or to TPWD for a hunter to be entered into the drawing.
- Mule deer harvested in the archery or extended MLD seasons were eligible for the drawing, if hunters contacted TPWD and brought their deer to be aged and measured by TPWD.
2024 Season Winners
First Place (1 winner) - Shyla Long
Ruger American® Rifle Predator in 6.5 Creedmoor sponsored by the Mule Deer Foundation
Second Place (5 winners) - Arlis McMullan, Jake Barten, Marco Hinojosa, Stephen Peterson, Steve Forest
$100 gift cards sponsored by the San Angelo Chapter of Safari Club International
Bucks Checked in 2024 Meeting the Restriction
