How to Conduct a Deer Camera Survey

By James Cash, Texas A&M WFSC ‘17

Photo Credit: Texas Parks and Wildlife Department

One of the most important components of a successful deer management plan is an understanding how your herd is responding to your habitat manipulations and harvest quotas. A common method for estimating deer densities is to use infrared triggered game cameras over bait sites. Camera surveys are perfect for properties where a lack of suitable roads or thick vegetation makes spotlight surveys impractical. Many people conduct camera surveys during August, September, or October to get a good pre-hunting season population density estimate and to scout for deer to hunt. Surveys can also be conducted after the breeding season, just make sure that they are conducted while bucks still have their antlers. Different habitat types and conditions will support different deer densities, expressed as acres per deer. For instance, in the Post Oak Savanah ecoregion of Texas 15 acres per deer (one deer for every 15 acres) is usually considered optimal. This number may be different in other areas of the state. 

 No survey method is perfect and camera surveys are no exception. Camera surveys can be impacted by malfunctioning equipment.  There is also evidence that camera surveys can underestimate the fawn/ doe population (Oetgen et al.). This may be due to intimidation by bucks around the bait site, or because fawns may be too young at the time of the survey to accompany their mothers to the bait site. Habitat conditions such as mast crop can also affect how deer will utilize your bait sites; and competing species such as feral hogs or even aggressive raccoons can scare away deer and eat all the corn. Despite these possible biases, camera surveys are still one of the best ways to estimate population densities on many properties. Just keep in mind that you are looking for an estimate of population densities that is useful for comparison over time. You are establishing a trend, not tallying the exact population. Combining camera surveys with spotlight surveys and harvest records will increase the accuracy of your population estimates.

Have one camera for about every 100- 160 acres. If you have difficulty getting this many cameras you can divide up your property and rotate the cameras by conducting separate surveys on different areas of the property one after the other. For instance if you have 1000 acres but only 5 cameras you can split the property in half and survey 500 acres at a time. Make sure each site gets a camera for 10 days and that you rotate the cameras consistently each year. Do your research before buying the cameras. Make sure you are getting the most reliable cameras you can afford to avoid camera malfunctions impacting your data.

After dividing your property into 100 acre units choose a camera site near the center of each unit that will be easy for you to reach and that you believe has the greatest chance of attracting deer. Mark each site on a GPS with an identifying number. Now the real work begins as you start the pre-baiting phase. Use your GPS to get to each of your camera sites. Bring along a bag of corn and something to trim branches with. Once your GPS shows you are within around 10 yards of your marked point begin looking for a suitable tree or other structure to hang your camera from. Areas lacking trees may require t-posts for the cameras to hang from. At this point you are not hanging cameras yet, but you want to make sure you are pre-baiting at the same location that you will put the camera in the future. Once your future camera location has been decided on pace off about 10-15 feet from the camera tree and dump half a 40lb bag of deer corn. Now is also a good time to trim back plants that may obstruct the camera’s view or cause false motion triggers. It may also be a good idea to take notes on the precise location of the bait pile so that it can be easily found in a few days when you come back to add more corn. Three to four days after creating your initial bait piles go back and add another half bag of corn to the piles. 

After a week of pre-baiting it is time to put up your cameras. Put each camera on your previously chosen trees/ posts and add more corn to the bait pile if needed. The camera should be angled so that the photograph will include the entire deer. Set your camera to motion sensing with 5 minute delays. Keep your camera up for 10 days, adding more corn if needed about halfway through the survey.

 

Photo Credit: Texas Parks and Wildlife Department

Analyzing results:

Upload all the photographs to your computer. You may want to keep track of where different photographs were taken, that way if a specific deer you are targeting is photographed you know where it was. Tally up the number of pictures of bucks, does, and fawns. If a photograph has multiple deer in it you count a photograph for every deer, so the picture above with the doe and fawn would count as one doe picture and one fawn picture. Also keep track of how many identifiable bucks were captured. For instance, you may have 100 pictures of bucks, but that doesn’t mean that there are 100 bucks on your property. Use antler and body characteristics to determine the number of individually identifiable bucks. You do not individually identify does and fawns. You calculate the ratio of individually identifiable bucks to the total number of bucks photographed to find the “population estimate multiplier” (Oetgen et al.). This multiplier is used to estimate the individual number of does and fawns based on the number of pictures taken of each. The following is an example of how to analyze your survey pictures, based on the procedures outlined in Texas Parks and Wildlife’s publication “Surveying White-Tailed Deer Populations Using Infrared-Triggered Cameras.”

Deer photographs: 300

Buck photographs: 100

Individual bucks: 20

Population estimate multiplier: 20 ÷ 100=0.2

Doe photographs: 130

Estimate of individual does: 130 x 0.2= 26

Fawn photographs: 70

Estimate of individual fawns: 70 x 0.2 = 14

Estimate of population: 60

Now that you have a population estimate, you can use these numbers to find other useful ratios. Find your deer density by dividing the acreage surveyed by the estimate of the population. If the sample data above had been collected on a 700 acre lease the density would be 700 ÷ 60 = 11.67 acres per deer. You can also use this data to estimate your doe to buck ratio and fawn to doe ratio, both of which are important numbers to consider when managing deer.

For more information on conducting camera surveys or for help interpreting your population estimates, contact your local county extension agent (http://counties.agrilife.org/) or TPWD biologist (http://www.tpwd.state.tx.us/landwater/land/technical_guidance/biologists/)

Tips:

-When taking bags of corn to the camera sites, carry the full bags to the camera points with short walks from the trail or road. After dumping half a bag at a bait pile that was a short walk you can save the remaining half bag to take to bait piles that require a longer walk from your vehicle.  

-Take your time aiming the camera. There’s nothing more frustrating than a bunch of pictures aimed at the ground that just show deer legs and hooves. You may have to wedge sticks behind the camera to get a good angle

-Use the same camera points each year.

-Bring extra batteries with you when you visit the sites to add more corn halfway through the survey. Some cameras tend to drain batteries much faster than others for no apparent reason.

-If you are new to using a GPS keep in mind that many require that you hold the GPS flat in order for it to give you the proper directional heading. Holding the GPS vertically may leave you wandering around the woods in vain with a bag of corn over your shoulder looking for your camera point.

Literature Cited

 Oetgen, J. G., B. C. Lambert, Jr., and J. D. Whiteside. Surveying white-tailed deer populations using infrared-triggered cameras. Texas Parks and Wildlife Department