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Determining Deer Densities in Tennessee

Over the years some folks have heard snippets of information about thermal imaging studies the TWRA has been conducting. One of the goals of our study was to determine if a direct measure of deer density could be obtained. Most agencies today use population models which often rely on harvest data. Although they are useful tools when used as an index, most folks realize that harvest data may not reflect the standing population. TWRA wanted to see if we could go out over a period of time, look at the standing herd, take some measurements, and use those measurements to calculate the deer density on the landscape level (countywide or higher). Thus the birth of the Area 22 Study.

Deer Transects Map

As nice as it would have been to go out and simply count deer, we knew that was not a viable option for coming up with an accurate population estimate. Without a doubt, we would miss deer on our surveys thus leading to a lower population than what was truly out there. Therefore our agency opted to incorporate a method called distance sampling. As complicated as it appears (trust us there's a lot of math), when it is described in the simplest, most folks can understand it.

Below is a link that will hopefully help folks understand distance sampling.

http://twraonline.org/DistanceSampling/Distance_Sampling.html

The first video describes how distance sampling works, while the second video works through a simple math problem and introduces our Area 22 Study. It is our intention to take these studies statewide to determine deer densities across our landscape.