Penn State Deer-Forest Study

We all know the adage – A picture is worth a thousand words.

Do you know what it’s not worth? A deer population estimate. Not even a thousand photos from a camera can tell you how many deer there are.

Trail cameras appear to be ubiquitous today. Everybody seems to have one. Duane and I are certainly part of that crowd. It’s fun to set them up and see what’s out there when we are not [Unless you’re Duane and the camera just tells you when you SHOULD have been at your deer stand]. We’ve used photos captured on our trail cams many times on the blog. In fact, those photos have inspired many posts.

deer in snowy woods; fawn hard look ear drop

Some people are very invested in the use of trail cameras running multiple cameras throughout the year. A friend of the Deer Forest Study and the blog shares photos and videos of our collared deer on a regular basis from the cameras he keeps in our study area.

Scrapes and collars aside, I have heard more times than I can count that “the deer population is down where I hunt; my trail camera shows that.” Actually, it doesn’t. Because unless you are running a survey and calculating estimates, merely seeing less (or more) deer on your trail cam says nothing about the population.

If you Google “using trail cameras for population estimates,” you get 36 million results in 0.46 seconds. Trail cameras CAN be used to estimate deer populations. One of the first evaluations of their use for population estimates occurred over 2 decades ago. Since then, many more studies have been published about the pitfalls, assumptions, and best practices of using this technique of population estimation with entire courses dedicated to camera trapping study design, data management, and analysis.

You can even find instructions online on how to set up your own camera survey to estimate deer populations. Texas A&M Natural Resources Institute, Mississippi State University Extension, and Perdue University Forestry & Natural Resources all have instruction guides.

MSU DeerLab breaks it down nicely. First, you’re going to need more than one camera. Recommended camera density is 1 camera/100 acres. Next you are going to need a map of the area. Divide the area of interest into 100-acre blocks then place one camera in each block. Be sure to set the camera on a 10-minute delay and face them north or south. Camera stations need to be baited as well. Run the survey for 10-14 days.

Collect the data from the cameras. Grab a datasheet and a pencil or get to a computer to analyze them. Math is involved. Suffice it to say it’s not just a straight count of the deer in the photos.

After investing all this time, energy, and money, you will get an ESTIMATE of the deer population.

What’s my point? Enjoy those trail cameras and have fun looking at all the pictures. But don’t put much stock in what you think it’s telling you about the deer population.

-Jeannine Fleegle
Wildlife Biologist
PGC Deer and Elk Section

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11 comments on “A Thousand Words”

I thought baiting was illegal and now in the age of CWD stupid as well, but it may give you an idea of how many deer you may be spreading it into.

Duane Diefenbach says:

January 26, 2022 at 11:55 am

Yes, in many places baiting is illegal and we would never encourage baiting. The method Jeannine mentioned was developed before CWD was a concern and was only necessary for the period of population estimation. There are now newer methods that do not require baiting.

Thank you.

I love the pic!

I’m a member of the Pittsburgh Sportsmens luncheon club. Would any of you be willing to do a zoom presentation of your group, research and results sometime to the club?

Excellent information. I will not be trying to estimate deer population. Thanks for this blog.

First let me say I really enjoy and learn from this blog, and do have respect for the experience of you and Duane. However I have an issue with your comment’s about “running a survey and calculating estimates”. Isn’t this what PGC essentially does when determining the allotment of antlerless doe license? It appears that the comments PA hunters have made over the past 20+ years about deer populations on the decline in many units is unaccepted by your department. Yes, some comments are un-validated, But many, with the consistent use of trail cameras over the years in these areas as well as good old fashion boots on the ground observation of actual sightings/droppings/trails/tracks/food availability/etc; have supplied the proof for these hunters to make such comments that the deer population has in fact declined. I would like to hear how you can disagree.

Duane Diefenbach says:

January 27, 2022 at 7:58 am

The PGC collects data to make inferences about the deer population and uses US Forest Service forest habitat conditions for each Wildlife Management Unit to make antlerless allocation recommendations to the Board of Commissioners. Those recommendations are based on Board-approved goals and objectives for deer management, which surveys show are supported by the majority of Pennsylvanians. The recommendations are presented to the Board of Commissioners every April and is available on the PGC website:
https://www.pgc.pa.gov/Wildlife/WildlifeSpecies/White-tailedDeer/Documents/2021%20Deer%20Population%20Report%2020210401.pdf

Each WMU is hundreds to thousands of square miles in size. Therefore, what any individual hunter sees on the few hundred acres ground they hunt (if that, I only hunt about 50 acres) is likely different than the WMU average. Also, individuals may have different goals and objectives with respect to deer and forest management.

Wildlife management is a top-down system in North America. Wildlife agencies are given the legislative authority to manage wildlife and set goals and objectives, with input from the public. However, they have no control over what happens on most of the lands in the state. If private landowners want more deer they should shoot fewer antlerless deer. If they want fewer deer they can enroll in DMAP. If they hunt <600 acres they are more at the mercy of what happens on adjacent properties than their own. This means of managing deer is a perfect recipe for discontent and discord, which explains the history of deer management in most of North America.
- Stan Rice says:
  
  January 28, 2022 at 11:04 am
  
  The last sentence in this paragraph is the perfect summary on this issue I have seen. Clear, concise, and 100%accurate.
  
  Wildlife management is a top-down system in North America. Wildlife agencies are given the legislative authority to manage wildlife and set goals and objectives, with input from the public. However, they have no control over what happens on most of the lands in the state. If private landowners want more deer they should shoot fewer antlerless deer. If they want fewer deer they can enroll in DMAP. If they hunt <600 acres they are more at the mercy of what happens on adjacent properties than their own. This means of managing deer is a perfect recipe for discontent and discord, which explains the history of deer management in most of North America.

Their is only way to tell how many deer are in any area. “Arial Surveys ”
The PGC did a few & the results shows what is really in an area. In my opinion, todays results wouldn’t meet today deer management objectives.
I don’t think the PGC would like to publish the real numbers. The PGC likes to use data that is a ” trend “. Besides the state is too big & manage with a few data points…

Duane Diefenbach says:

January 28, 2022 at 12:54 pm

Actually, aerial surveys aren’t as good as many people think they are. We wrote a whole series of posts on estimating deer populations and you can read it here
https://www.deer.psu.edu/moving-the-chains/
For most species of wildlife it is too expensive to estimate abundance, and for deer there are more important things to know than how many there are (like how are they affecting forest regeneration). Thus, many wildlife species are monitored for trends because knowing that pattern is sufficient for making management decisions.

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