Trail-Cam Surveys: More Than Just Pretty Pictures
Every summer and fall, deer hunters capture millions of trail camera photos across the whitetail range. Most will receive a quick glance before being deleted or filed into the “black hole” of your computer’s hard drive. If the photo contains a big buck or some “cool” factor, then it may end up on social media at best. But for those who actually study their trail camera photos, there is much more that the picture can tell them. In fact, those who run summer/fall trail camera surveys will go into the season knowing exactly what they need to do in order to create a better deer herd.
What is a Trail Camera Survey?
Hearing someone talk about doing a trail camera survey may sound intimidating, but really most of us are likely already running a form of the survey, we just need some minor tweaks in the setup. A trail camera survey involves a simple setup of cameras for a certain number of days, and then an analysis portion.
In the end, instead of just seeing a “cool picture,” you gather extremely valuable information on the deer roaming your property that will not only determine the current status of the deer herd on your property, but also help you make better decisions this season.
Site Selection and Setup
Like I said before, most of us already run a form of survey. The first step is to determine the number of trail cameras you need for your property. There are two options here: a camera per 100 acres or per 200 acres. For smaller properties or those with little wooded acreage, a camera per 100 acres is best. For larger parcels of land, a camera per 200 acres will work. What’s the difference? Observability. This is the percent of individual deer you will photograph on a property. Most hunters think they get the majority of deer, especially bucks, on camera that use their land. But, in reality, you are likely not getting more that 70 percent of them!
Cameras should also be placed in proportion to the different habitat types on your property. For instance, if your property is 50 percent woods and 50 percent fields, then half of the cameras should be placed in woods and half in the fields. Why? Well some deer prefer woods over field, and vice versa. This ensures you are not biasing your survey based on habitat selection by an individual deer.
Although a highly debated topic, camera surveys require baiting the site. The most commonly used attractant is shelled corn. Corn should be placed no more than 15 feet from the camera, and the site should be cleared of any debris, weeds, or structures that might obscure part of a feeding deer. I also like to spread the corn in a wide “U-shape” on the ground, so that multiple deer can feed at the pile with reduced competition. Often a site will get a dominate buck or doe on the corn which will reduce the number of individual deer you photograph. No feeders should be used for surveys as they always block important pieces of information like antlers or body characteristics on a deer.
Any object including weeds and grasses can cover important characteristics of a deer, one easy way to make sure no vegetation blocks anything is to break out your weed trimmer and clear the site. (Jeremy Flinn photo)
With today’s technology there is literally thousands of combinations for camera settings. For a trail camera survey it is pretty standard, but one that many hunters may scratch their heads on. Trail cameras should be set on one picture with a five minute delay in between images. Five Minutes? Yes, that’s the way the calculations are set up. An average camera survey can bring in well over 3,000 images, so why put it on a more frequent setting. Yes, you may miss a buck after a doe triggers the camera, but the odds of him coming back are really good because of the corn at the site as well as time.
Duration of the Survey
Time is a trail camera survey’s best friend during the summer/fall. The longer the survey runs, the greater the percentage of the herd you observe, to a certain extent. One critical mistake that those who do surveys make is not pre-baiting. Pre-baiting the site allows the deer to discover the corn and start visiting regularly. Usually a two to three day pre-bait period will be sufficient, unless you had previously been feeding at the same area, like in a protein feeder. It’s worth noting that all feeders should be empty during the survey so they aren’t outcompeting your camera survey sites. Most surveys will then run between ten to 14 days. At 10 days and a camera per 100 acres, you are likely to capture about 85 percent of the population, and the extra four days will get you to about 90 percent observability.
Even though it may seem like a lot of work, the setup is really easy. I can typically setup seven to ten trail camera sites in four to five hours. What takes the longest is the analysis. You can always outsource this to a professional wildlife biologist, but let’s break it down as a DIY project. There are four main parts of the analysis to complete before you can see the results: Counting, Uniquely Identifying Bucks, Aging & Scoring, and Calculations.
Just as the name suggests, the first step after all the pictures are collected is counting the number of bucks, does, fawns, and unknowns (you know it’s a deer but just not what category to place it). If there are three bucks in a picture it counts as three. Even if you know it’s the same buck in 30 straight pictures, it counts as 30. That’s because we are looking at the number of occurrences, not the number of individual bucks at this point. These overall numbers will come into play a little later for the calculations.
Uniquely Identifying Bucks
One of the coolest parts of the entire survey, in my opinion, is uniquely identifying bucks. It’s beneficial when doing the counting to move all the images with a buck in them to their own “Buck” folder. Then you only need to examine that folder for this part. You will do a lot of side by side comparing, and likely will find several bucks you called different deer at the end of this section, are actually the same. I always keep multiple antler angles of each buck, and at least one good full body, broadside shot for aging.
Aging & Scoring
Aging and scoring bucks on the hoof is much more of an art than it is a science. That being said, having someone very experienced at this point is critical as the decisions made here will dramatically affect the end results of your survey, and particularly how you hunt this fall. Typically, scoring a buck can be in increments of five inches or 10 inches as this will give you a good idea of where you stand. Score all of them including one and a half year olds as all the data is important, even if it is a 15-inch gross score spike. Aging should be done in classes such as, one and a half, two and a half, three and a half, four and a half, and five and a half plus. Use your best judgment and also look at last year’s trail camera pictures to see if it helps put an age on him.
At this point you can create very descriptive graphs of average antler size by age class. You can also determine which bucks are “shooters” and which ones need another year or two, based on age and antler size.
The calculations are a set of very simple mathematic equations. The Mississippi State University Deer Lab (www.msudeerlab.com) did a phenomenal job of putting together a great guide for equations. The first thing we have to do is determine the number of unique bucks, does, fawns, and unknowns in the population. Well, we know the unique bucks from a previous step. Using that we can figure out how to determine all the rest.
Let’s say on our 200-acre property we uniquely identified ten bucks, and we had 1,000 buck occurrences in the photographs. We divide the number of unique bucks by total buck occurrences to get the “Population Factor.” The Population Factor is what we use to estimate the number of unique does, fawns, and unknowns.
So here is the scenario to calculate the Population Factor:
10 unique bucks / 1,000 Total Buck Occurrences = 0.01 (Population Factor)
Now we multiply the doe, fawn, and unknown occurrences by the Population Factor to get the unique individual estimates:
3,400 Total Doe Occurrences X 0.01 = 34 Unique Does
1,700 Total Fawn Occurrences X 0.01 = 17 Unique Fawns
500 Total Unknown Occurrences X 0.01 = 5 Unique Unknowns
Add the unique individuals together to calculate total population:
Unique Bucks = 10
Unique Does = 34
Unique Fawns = 17
Unique Unknowns = 5
TOTAL DEER = 66
Now the calculations are easy. Here are some of the more popular ones:
Adult Buck to Doe Ratio = Total Unique Bucks : Total Unique Does
Our Example – 10 : 34 or 1 Adult Buck : 3.4 Adult Does
Fawn Reproduction = Total Unique Fawns / Total Unique Does (expressed as a percentage)
Our Example – 17/34 = .5 or 50%
Deer Density = Total Acreage / Total Deer
Our Example – 200/66 = 3.03 Acres per Deer
The trail camera is one of the most underutilized tools we have as deer hunters and managers. It’s so much more than something that takes “pretty pictures,” it’s a gateway to an in depth look into our deer herds. When used properly, you will be able to fine tune the herd and make every pull of the trigger or release of an arrow a more sound management decision.
For more information on trail camera surveys, contact the crew at www.buckadvisor.com or through their Facebook page.