Most deer hunters start getting “the itch” by the time late summer rolls around. It’s during this time of year that those game camera photos really start to show hunters the potential of bucks on their ranch or hunting property. For the guys with ongoing white-tailed deer management programs it can be very, very exciting to see what those young bucks of years past have transformed themselves into. With the amount of rainfall we’ve received in Texas this year hunters should expect a really good year!

Abundant rainfall throughout in the early part of the year combined with scattered, timely rains throughout the summer have kept much of the deer habitat green and growing. And as most of us in the Lone Star state know, rarely does the ground look green in Texas going into August. All that valuable precipitation has maintained the deer herd in good condition throughout what is typically the summer stress period—but not this year.

Ranches in the Hill Country have already reported outstanding fawn crops with does with twin fawns being the rule rather than the exception. Although casual observation can give a deer manager some information about a whitetail herd, nothing informs a hunter about what is happening on their property better than pre-season deer surveys and harvest data collected during the hunting season. Regardless of the habitat found on your property or where it is located, there is a deer survey method that can work for you.

I really do enjoy this time of year. Not only are hunters heading out to their properties to set out, repair, or otherwise inspect hunting blinds and feeders, but more than ever hunters are using game cameras to scout out the deer herd in their areas. I think game cameras are great for making deer hunters more knowledgeable than ever before. They allow hunters to watch a trail, roadway, watering site, or feeder 24 hours a day, 7 days a week, and give them a good idea of what to expect during the upcoming season.

Hunters can also use camera photos for aging deer on the hoof in addition to scoring deer on the hoof. This allows hunters to become more familiar with both of these tasks as well as identify photographed bucks in the field very quickly. In addition, landowners or hunters can also conduct deer surveys using game cameras, but certain precautions must be taken to accurately estimate the deer population in the area.

So August is here, bucks are nearing the end of their antler growth, hunters are sweating it out at their hunting ranches, and everyone is getting excited about the upcoming deer hunting season. It’s been a good year for deer thanks to the rain and I’m expecting most hunters to do really well this year, unless we have a warmer than average winter—then all bets are off. If you passed up some middle-aged bucks last year I think you are in for a real treat this year. Now let’s get out there and get to work!

From the looks of things, Spring has definitely sprung here in Central Texas! Browse plants are putting on new leafy growth and the moisture-rich soil is covered with high-protein forbs. It appears the white-tailed deer found in this part of the world be eating good for some time to come. Let’s just hope the all-important Spring rains come through for the deer habitat this year. So far, so good. Changing subjects now, and I know it’s a long time until deer survey season, but I recently learned of an interesting study taking place out of Texas State University. The research relates to conducting stand surveys to estimate white-tailed deer populations on individual ranches.

First, I’ve never been a huge fan of stand surveys for whitetail, primarily because I feel other deer survey techniques do a better job of estimating deer populations on individual properties. That being said, some properties just do not lend themselves to being surveyed any other way, so even a low-confidence estimate is better than no estimate at all. In the mentioned study, a high-fenced pasture with a known number of marked white-tailed deer was used. Five deer stands and 5 timed spin-feeders filled with corn were placed within the pasture and were located approximately 1/2 mile from one another, creating a hunting scenario similar to many Texas ranches where deer are hunted.

Surveys were conducted from stands from 6:00-8:00 a.m. and p.m. from September 1-15 in 2007 and 2008. Because deer were marked with numbered ear tags, it allowed observers conducting the surveys to attempt to identify the animals as well as possible (as hunters would), but then the ear tags also allowed observers to accurately identify individual deer. This gets to the heart of the problem that many deer managers have when counting deer from stands: Is the doe that just walked out of the brush the same one that headed that direction 5 minutes ago?

During the survey period, one observer would count from each of the 5 deer stands during both the morning and evening. The number of deer observed at each stand during each 2 hour survey period were combined. And for those hunters that sometimes sleep in, you may rest a little easier knowing that, on average, the number of deer spotted during evening surveys were higher than the number of deer spotted during morning surveys. I would have guessed the complete opposite, primarily because I prefer morning hunts. But then again, 3 of the last 4 whitetail bucks that I have bagged have been shot in the evening.

In addition, researchers found that habitat conditions impacted stand counts. The years of 2007 and 2008 were completely different: One was wet, the other was dry. During the wet year, 1/3 of the deer were spotted only once during any 4 consecutive counts when all 5 stands were surveyed on the property. This meant the remainder of the deer were seen more than once, but for hunters that would be counting unmarked animals it would be very difficult to determine if individual deer were previously counted. During the dry year, deer were more readily observed (as you would expect with bait/feeders), but in many cases the same deer were seen by various observers at different stands during the same morning or evening survey. This could cause potential problems with over-estimating the deer herd found on a property.

In closing, this stand survey study has merit, but there are a lot of variables that determine the potential for seeing deer that will vary between ranches. Habitat conditions obviously play a role in determining feeder visitation by deer, but so would deer density (on different ranches or even the same ranch during different years). When properly conducted, I think stand count surveys can be effective at determining a property’s buck to doe ratio or annual fawn production. However, much caution should be used when attempting to use stand surveys to estimate and manage an area’s deer population.

Late summer is not just a stress period for wildlife, its also the time of year to survey white-tailed deer! If you regularly perform surveys on your property, you know the importance of conducting annual population estimates. For those of you that do not, surveys allow deer managers to get a snapshot of the local deer population just prior to hunting season. Without this information, it’s difficult to make harvest recommendations that fall in line with your management objectives.

The first piece of data you need going into the fall is a deer density estimate, or how many acres are available for each deer.  In central Texas, where I am located, a good rule of thumb is to 8 to 10 acres of good deer habitat per deer. Free-choice supplemental feeding can drop that to about 6 acres per deer, but one thing to keep in mind is that typically as deer density goes up the quality of individual deer goes down.

The best way to estimate deer density is to perform spotlight surveys. The information collected during spotlight surveys not only includes the number of deer spotted during the census, but also the amount of acreage that was actually observed during the survey. For example, if you have a ranch that is 1,000 acres, you can visually see 200 acres during your census, and you count 20 deer, then you have 100 deer on your property. Without good visibility data the spotlight count data will be worthless.

The next piece of the puzzle you will need to estimate your fall herd is to perform daylight observation surveys for deer. These are simple surveys because you can do them anytime you’re out on the property during daylight hours. And let me stress that although the data is easy to collect it can be of greatest importance! During daylight surveys simply record the number of bucks, does, and fawns observed each day. It’s that simple. But don’t guess! If you can’t tell what it is, don’t skew the data by guessing.

Oh, and you may be wondering why deer are surveyed during the late summer and into the early fall? Well, it’s because it’s at this time of the year that we can readily see deer, so that helps get the most accurate buck to doe ratio for a given area. In addition, essentially all of the fawns are born for the year and are moving around, so we can compare the number of fawns seen on our daylight surveys to the number of does to get a fawn crop estimate. 

Here’s an example: If you record daylight observations from August 1st to September 15th and you see 200 bucks, 400 does, and 200 fawns, then we can estimate the herd composition to be 1:2:1, or 1 buck for every 2 does and 1 fawn (25% bucks, 50% does, and 25% fawns). We can also estimate the fawning rate to be 50% since only 1 fawn was observed for every 2 does.          

Once fall deer population surveys are completed, deer managers can look at both the herd composition, density estimates, and the latest fawn crop to adjust the harvest rates to achieve their desired goals. Making a sound harvest recommendation is a science with a bit of an art thrown in since habitat conditions and fawn crops change annually, but collecting and analyzing deer survey data should be a part of proper harvest management.

Aircraft, including both helicopter and airplanes, can be effectively used to obtain deer density, sex ratios, fawn survival, and deer distribution information in some portions of the US. Although more expensive to conduct than the spotlight and mobile deer surveys, the aerial survey does provide the necessary population data in a short time frame. This information can be utilized to provide harvest recommendations for the entire ranch, as well as individual pastures. So, does a helicopter survey make sense for your deer management program?

The helicopter survey is considered by some to be the most accurate census for determining populations on a given unit of land. However, the total number of deer recorded on helicopter surveys should not be considered a complete count of all deer. Studies indicate that accuracy of helicopter surveys in South Texas brushland is fairly consistent, but they can underestimate deer density by 60-70%!

As a result, the information gathered from this type of survey should be used only as population trend information and for the preparation of annual harvest recommendations with the understanding that the deer density figures are probably conservative.

Helicopter Surveys

For aerial surveys using a helicopter, surveys should start approximately 15 to 30 minutes after sunrise. On ranches with dense vegetation and/or hills, it is recommended to start at least an hour or more after sunrise due to shadows. Of course, the drawback to starting later is that deer movement is reduced — so you need to keep some of these factors in mind and make sure that survey techniques are consistent over time.

On smaller ranches, or those located in open country, the entire ranch can be surveyed rather than sampled. The survey should be flown by pasture because this provides shorter transects and a good flight line can be maintained. Most often aerial surveys are conducted with both a pilot and an observer with each counting the deer observed.

The observer records all bucks, does, fawns and any unidentified deer spotted. This data should be recorded on a data sheet rather than a tape recorder as information may be lost due to tape malfunction or garbled due to aircraft noise. Data should be collected by pasture if a complete ranch survey is being conducted.

The observer may also record bucks by point-class (2-3, 4-7, 8-9, or 10+ points) to provide additional information. However, I wouldn’t suggest flying off from the transect to collect this information. If data is collected in this manner, then you can establish harvest ecommendations by pasture. This is an important consideration if the landowner or manager is leasing by pastures to several groups or otherwise needs to manage the harvest by pasture.

Ideally, transects should be flown on north-south bearings. This eliminates the observer and pilot from looking directly into the sun and missing deer. This is not always practical due to terrain or other obstacles that may be in the flight path. Another consideration is wind direction. Helicopter pilots prefer to fly into the wind when possible and the wind does not always blow from the north or south. Survey altitude will normally be from 30-50 feet above ground level. Flight altitude is also dependent upon terrain, vegetation condition, type, composition and any manmade obstacles that occur on the ranch.

Difficulties in locating and counting deer can be expected where heavy, close-growing stands of cedar, oaks and/or a combination of tall over story of trees with heavy brush undergrowth. Aerial surveys may not be suitable on ranches that have near complete canopy closure of evergreen species that reach heights of 10-15 feet. Shin oak, open ranches, or brush country is not as problematic because running deer are still readily visible.

In dense vegetation, deer will not readily move from the sound of the helicopter. For individual pastures it is better to initiate the count in the densest portion of the pasture and work toward the more open areas. Likewise the hillsides should either be worked from top to bottom or bottom to top depending on location of open areas.

Actually Counting

Veteran observers develop their own technique for counting deer. But all basically agree that an observer should not only look ahead but also scan to the side and to the rear of the helicopter. Also, in thick vegetation it is advisable to look through the vegetation rather than looking at the top of the vegetation.

Timing of aerial surveys is important. Ideally, deer population information is collected during late summer or early fall (August to November) to have the most current information when developing harvest recommendations. In areas where deciduous species are the dominant species, it is necessary to wait until after leaf drop (late fall/winter). Ranches with sparse vegetation may be surveyed as early as mid-August.

Permit Required

Before any aerial survey can be conducted, most states require that a permit form be filled out and submitted for approval. The owner of the helicopter must also be permitted by the state of the survey in order to operate this type of business.

Population estimation of white-tailed deer is an important cornerstone for the development of deer management strategies. However, estimating deer populations in heavily forested regions is difficult because of reduced visibility. Traditional survey methods, including spotlight counts and aerial surveys, provide limited results in dense forests. So now what?

The use of game cameras, or trail cameras, can provide photo records of an individual deer, a deer herd, and important parameters such as population estimates, sex ratios, and productivity. In an attempt to estimate a deer herd using game cameras, a census project was carried out in 2004 in the piney woods of east Texas, on a property 1,002-acres in size. A total of 7 cameras were placed out (1 trail camera per 150-acres) from September 2 to September 12.

A total of 158 photographs of deer were taken during that time. Twenty-three buck, 97 doe, and 48 fawn photos were collected/observed. Of the 23 total buck observations, 15 individual bucks were identified. The buck to doe ratio was calculated to be 1 buck:4.2 does (23 bucks:97 does). Since 15 individual buck photos were taken, 15 was multiplied by 4.2 to give a doe population size of 63 animals.

The doe to fawn ratio was 1 doe:0.50 fawns (97 does:0.49 fawns). The doe herd of 63 was multiped by 0.49 to put the number of fawns at 31 animals. Using the data/photos collected from the 7 game cameras, the total population of the 1,002-acre ranch was estimated to be 15 bucks, 63 does, and 31 fawns, for a total of 109 animals and a density of 1 deer/9.2 acres.

Their results concluded that buck-to-doe ratios were skewed, the fawn crop for that year was higher than average, and the deer density was above average. If this data is accurate, then recommendations should include continued doe harvest while limiting buck harvest to only mature bucks, if improving sex ratio and buck quality are a goals.

Their photos showed that most bucks photographed were 1 1/2 to 2 1/2 years old. Obviously, protecting these young animals will increase the number of mature bucks, improve sex ratio, and increase buck antler quality.

My Two Cents:

I think game cameras do have a place in deer surveys. However, there are a few problems with this particular study. First, the study takes place on an unknown population of deer. Granted, it’s very difficult to get an exact deer density, but I would like to have seen other population estimates based on the other survey methods mentioned previously.

In addtion, there is likely bias towards under-estimating doe and fawn numbers. Fall surveys under-estimate their numbers because of their smaller home range sizes. In addition, bucks tend to dominate limited food sources because of their larger body size.

Regardless, game cameras do provide valuable information on buck age structure, the progression of individual bucks over time, good estimates of fawn production, and provide trend data to monitor a deer herd over time.