Ask The Biologist

So how exactly do states determine how many permits to issue every year?

QUESTION: The gun season in my state is bucks only unless you are selected for a doe tag. Then you can shoot any deer. The number of doe tags given out changes, sometimes a lot from year to year. My question is, how do they decide how many doe tags to give out? — John D.

ANSWER: You neglected to mention which state you live in so I can’t answer directly. But I can provide insight into how some states decide the number of doe, antlerless or any-deer permits to issue.

Many wildlife biologists use formulas that incorporate several variables to decide how many antlerless deer can or should be harvested in a given season. One of the most important sources of information is previous year’s harvest.

From this they look at things like the age and sex ratio. A high proportion of young deer in the harvest might indicate a growing population, suggesting more permits could be issued. A low proportion, fewer young deer, might be cause to scale back on permits. A higher proportion of bucks might suggest too much hunting pressure is being directed toward the male segment of the population and more antlerless permits might alleviate the problem, provided the herd can support higher doe mortality.

Another thing they look at in the harvest is hunter success rates. Not every hunter is successful, so biologists look back over previous seasons to see what the average success rate of permit holders is. This tells them how many permits they need to issue for a specific targeted harvest rate. For example, if the success rate is 25 percent and they want to remove 1,000 does from a particular unit or district, they would issue 4,000 permits.

They might also look at things like average weights and yearling antler beam diameters. By comparing this to previous years and long term averages they can evaluate the herd health and whether it is in balance with available food resources. If not, they may try to remove more deer.

This can further be supplemented with a browse survey, an analysis of the level of browsing. Over-browsing is a sign the deer population is too high. In northern states they also factor in something called a winter severity index, from which they can estimate how many deer survived the winter and what kind of shape they’re in.

Once the biology is finished, they must then evaluate the impact deer have on the landscape and people they share it with. Often, harvest levels are set to keep the herd well below what the land and habitat can support, and around what the non-hunting public will tolerate. This is called cultural carrying capacity.

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