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WAFWA Mule Deer Working Group

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The West that Was . . . No Longer Is

Losing Ground

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Precipitation - A Driving Force

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Elk and Mule Deer Interactions

Mule Deer Regions - No Two are Alike

Plant Communities in Trouble . .

Mule Deer Diseases

Supplemental Feeding - Just Say No

Learning By Doing

Managing Deer Herds with Harvest

Our Summary

WAFWA

Managing Deer Herds with Harvest

Hunting is the wildlife biologist’s most often used tool to effect changes in the size and composition of mule deer populations. Establishing hunting seasons and harvests are within the control of fish and wildlife managers, and this activity generates much needed revenue for conservation programs.

The recipe for success to create effective hunts is to be very specific about the desired results. Harvest and population structure are monitored closely so that hunting seasons can be adjusted to properly manage mule deer herds. All of this must be done with the support of internal and external constituents. If any piece of this recipe is missing, it is very likely hunting will be ineffective in managing mule deer.

Some of the most useful harvest strategies include buck-only seasons, antlerless harvests, changes in season timing and length and limited licenses.

Buck-only seasons

Buck-only seasons generally have little effect on mule deer populations because the remaining bucks breed all reproductively active does. Wide buck:doe ratios and an abundance of younger males may delay the timing of breeding, but there is no evidence this significantly affects the reproductive rates of does or the number of fawns that survive to adulthood in a mule deer population.

Some people have expressed concern that heavy, buck-only harvest degrades the gene pool of a population, but there is no evidence to support loss of genetic diversity as a result of younger males breeding does. Buck-only seasons can effect changes in age structure, sex ratios, and timing of breeding, but these do not significantly affect the population as a whole. Under normal conditions, fawns are born at a time when habitat conditions are optimal. There is concern that if breeding is significantly delayed, fawns may be born late, and have a more difficult time surviving during winter.

Antlerless harvests

Doe harvests can be effective tools for managing population levels. Antlerless harvests can prevent large-scale die-offs or overbrowsing of habitat. The population has to be monitored closely, and the manager has to have reasonable estimates of population size, and adult and fawn survival. Each of these factors will allow biologists to use adaptive resource management techniques to manage mule deer populations and their habitats. Biologists know that:

- Harvesting does can be used to decrease a mule deer population depending on whether or not the removal of the does is additive or compensatory mortality. If the desire is to reduce the population, enough does must be harvested to reach the level where mortality is additive.

- By understanding how doe harvest affects a population of deer, managers can better meet population objectives within a habitat.

Studies have shown that most environmental factors that reduce survival of fawns have little effect on adult does, which have a low natural mortality.

Season length and timing

Managing season length and timing are two methods managers have used to attempt to alter the age and sex structure of mule deer populations, especially when hunters become vocal about too many hunters, too few bucks or too few large bucks.

Restricting season length reduces hunter days in the field, but doesn't necessarily reduce buck harvest or improve buck:doe ratios.

Hunting seasons used to occur over relatively short periods of time. Today, many states and provinces offer a range of hunting seasons over a longer period of time and with a variety of harvest methods such as muzzleloader, archery and centerfire rifle. The purpose of expanded seasons is to offer additional types of hunter opportunity and reduce hunter densities to improve hunt quality and lessen landowner/hunter conflicts.

Antler point restrictions

Creating mule deer harvest seasons with antler point restrictions is popular amongst hunters who think it will help increase the number of mature bucks and buck:doe ratios in mule deer populations. But research in many western states shows that antler point restrictions do not produce more deer or larger-antlered deer.

Colorado implemented antler point restrictions statewide for six years, and in a number of game units for seven years. The result was a shift of hunting from pressure on all age classes of bucks (primarily yearlings) to bucks two years and older, and an increase in illegal or accidental harvest of yearling bucks. The number of mature bucks did not increase over time.

Idaho and Montana implemented two points or less seasons to reduce hunting pressure on older bucks and improve buck:doe ratios at the end of hunting seasons. Over the long term, two point seasons did not improve buck:doe ratios at the end of the hunting seasons.

Wyoming’s experience with four point or better seasons resulted in fewer hunters and a reduction in total harvest, fewer mature bucks, and a significant number of deer harvested with fewer than four points.

Utah abandoned efforts to implement antler point restrictions after five years when officials documented illegal harvest, reductions in overall harvest and fewer mature bucks.

Attempts to increase the number of mature bucks and buck:doe ratios using four-point seasons in Montana reduced buck harvest by 28 percent, increased illegal harvest of bucks with 3x3 points or less by about 40 percent, and increased harvest of bucks having more than 3x4 points.

Washington tried antler point restrictions in a few of their hunting units and experienced a smaller harvest of mule deer bucks, a switch in harvest from mule deer to white-tailed deer, and no increase in the number of mature bucks. They did experience an increase in buck:doe ratios because of the lower buck harvest and improved recruitment of fawns.

Oregon abandoned antler point restrictions in a few popular hunting areas when the number of older bucks and buck:doe ratios decreased after 12 years.

Most western states have concluded that changes in buck:doe ratios and increases in the number of mature bucks can only be accomplished through reductions in harvest of bucks.

Limiting licenses

Limiting hunting licenses is another way to manage harvest and meet population objectives. In some areas, mule deer populations have not been able to keep pace with human populations, and demand for harvest exceeds availability. In these areas, biologists have little choice but to limit the number of hunting licenses.

In other areas, several years of severe weather forced states like Colorado to limit mule deer licenses. The state saw a corresponding increase in mule deer numbers as weather conditions improved and fewer mule deer were harvested.

By limiting licenses, fish and wildlife agencies offer fewer big game hunting opportunities, but can more effectively improve the number of large bucks, post-season buck:doe ratios and buck age structure.