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MDNR's Deer Population/Harvest Estimate Methods

The question, "How does the MDNR get their numbers of the deer population and harvest?" comes up frequently on these boards. The material below comes from the MDRR's website.

Keep in mind that we/they are dealing in a very mysterious and difficult for the layman to understand realm of statistics. I've never taken a stat class in college, never having the need to...thank God....but I know many who have and I can tell you the class(es) are no piece of cake fluff course. You get into the mind boggling twisting and turning pathways that lead through the intricacies of math with stops off at social/human behavior characteristics.

Am I a staunch defender of the method(s) the MDNR uses for their population/harvest estimates? No!

Am I a rabble rouser who scoffs at any and all statistical data offered by the MDNR? No!

I keep an open mind, remembering that just because I don't fully understand how something is done or...and sometimes, unfortunately, just because I don't understand how it works I don't believe it's true. That's a fatal flaw of some people's human nature.

In the past on these boards I've voiced my concern over the accuracy of the MDNR's data especially in the area of harvest numbers. However I feel that the mind needs to be open and I've had mine opened. That email from the Ohio DNR wildlife biologist (deer specialist) that touted the MDNR's method over Ohio's mandatory deer check-in is an example of a mind-opening experience.

WI, another state with mandatory deer check-in says their method is the only way to determine the kill. Again, this came in an email from a WI DNR deer biologist.

I'm not sure if both states use the same method of check-in. I'll have to email the Ohio biologist and ask him.

Here, from the MDNR's website is how they do it.Scientific estimates of wildlife numbers and information about population trends (increasing, decreasing, or stable) are necessary to successfully manage wildlife. For more than 50 years, the Michigan Department of Natural Resources (DNR) has worked very hard at estimating the size of Michigan’s deer population. Each year, wildlife biologists use this population estimate to adjust hunting season rules and regulations to meet the DNR’s long-range deer management goals to.…
.White-tailed deer populations, like other wildlife species, fluctuate in size from year to year, as well as from season to season. Annually, they reach their highest number by early summer, following the birth of fawns. Predation, disease, vehicle-deer crashes, hunting harvests, and winter losses due to starvation reduce their numbers during the rest of the year. Various survey techniques have been designed to assess these losses and provide wildlife managers with information to estimate the size of Michigan’s deer herd. These techniques fit together like the pieces of a jigsaw puzzle all of them are needed to see the entire picture. Following is a brief description of the time-tested surveys that the DNR has relied upon for managing Michigan’s white-tailed deer.

Deer Harvest Surveys

Hunting harvest information is the foundation for monitoring the deer herd. Hunting is the major source of population reduction. Mail surveys, rather than mandatory registration, are used to estimate the legal deer harvest each year. Following the 1999 deer season, nearly 1-out-of-16 deer license buyers were mailed a survey questionnaire requesting information about their hunting season results. These scientifically random samples of license buyers provide reliable estimates of the deer harvests by county. Hunter success and the ratio of young to older-aged deer in the harvest provide wildlife biologists with additional information about the status of local deer populations, such as population growth and sex ratios. Scientists around the world recognize our mail survey techniques for their excellence.

Summer Deer Observations

For nearly 70 years, DNR wildlife biologists, conservation officers, foresters, and other field employees have recorded the numbers of deer seen during daylight hours during the period from July 1 to October 31. Changes in sighting rates (the number of deer seen per hour of effort) reflect changes in the deer population. Summer deer observations provide wildlife biologists with one measure of fawn production that is critical for estimating population size. Deer observations are also useful for forecasting upcoming hunting seasons, identifying areas where deer numbers are changing, and for assessing the sex and age composition of local deer populations.

Check Station Data

Last year, DNR employees checked and recorded physical data for approximately 43,000 hunter harvested deer brought to highway deer checking stations and DNR offices. Experienced deer "agers" determine the sex and age of each animal, count antler points, measure antler beams, and check the general condition of each deer. Deer are also examined for bovine tuberculosis. Antler points and beam diameter measurements provide biologists with an index of the physical condition of local deer herds. Age and sex information for harvested deer is compared with similar information obtained from summer deer observations, to assure that the best available data are used for estimating the deer population size each year.

Traffic Survey

The sole use of the deer traffic survey is to provide an early estimate of the firearm season deer harvest. Michigan’s strong deer hunting tradition has always captured the interest of news reporters who are eager to report the deer hunting season results. DNR employees count deer on vehicles as they pass by observation points along the four major north-south highways in the Lower Peninsula. Deer "agers," who are stationed at deer checking stations at highway rest areas, help with this estimate. They determine whether deer are visible to highway counters. The traffic survey results are then adjusted for those deer that are not visible to highway counters. The results of the deer traffic survey closely match with mail survey results, which are not available until spring.

Pellet Group Surveys

DNR field employees are busy with deer pellet surveys during the spring season. This survey provides a useful index of deer distribution and abundance from year to year in the northern-forested areas of the state. Pellet group surveys do not work well in areas where intensive agricultural activities disturb evidence of deer. Since 1950, field employees have counted pellet groups along random survey courses to determine the relative number of deer within a defined area. These counts are generally expressed as deer per square mile.

Dead Deer Searches

Dead deer searches are done in conjunction with pellet group surveys. Teams of Wildlife personnel count the number of dead deer they locate while walking pellet survey courses. When a carcass is found, a determination is made whether the loss occurred during early or late winter. Over-winter loss is a major source of non-harvest mortality to deer on the northern fringe of their range. The results of dead deer searches are used with pellet group surveys to estimate spring deer populations.

Car-Deer Crashes

A common deer population index in the Midwest is the number of car-deer crashes reported to law enforcement officers. Several research studies from across the country indicate that car-deer crashes are related to road densities, traffic volumes, and deer densities. The Michigan State Police and the Michigan Department of Transportation maintain data on the number of car-deer crashes and traffic volumes. Recent findings by Michigan State University demonstrate the usefulness of these data to wildlife managers since a correlation exists between county car-deer crashes and the buck harvest. Car-deer crashes are also used to estimate additional non-harvest mortality.
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Whit1
 
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Thanks Whit, for the info. I have posted recently about this topic and 100% agree that the MDNR's system is by far, more than adequate less expensive and time tested.

The main reason there is mandatory check in of deer is due to the natural skepticism of deer hunters. Not too many belive in our system. They select one part of it, (bridge counts) and make it look like it is an amatuer effort to count the deer, never once admitting that this bridge count is used only for an early estimate to satifsy the curiosity of you know who. Dammed if you do, dammed if you don't.

I will repeat what I have posted earlier. Mandatory check in works great for a couple of years, then it covers no more than 60% of the actual harvest. This means that they have to use other guess work to fill in the gap. So they are right back to using the survey method as a major means of estimating the deer numbers.

The winter pellet count does work, but no better than the pellet counter. You do not find as much support from DNR personnel for this antiquated method. A new and proven method of counting deer during the winter is an arial count using the latest Infra Red Imaging devices. They cost quite a few bucks, but take video for record keeping and the deer cannot hide from you even under conifer branches. This same method can be used for the dead deer count, which is rarely used now. The reason it works for dead deer is due to the dead deer gatherering heat from the sun during the day and at night it cools down much slower than the ambient air temperature. They stand out out the beacons of light houses. I have used this device and I'm impressed with it. The uses are endless, law enforcement of all sorts including poachers, finding lost people in the woods, counting the fawn count in early june, locating these same fawns for a tagging operation and much more.

My property was used as a location for a dead deer count in the 90's. They use a mile long straght line and observe for 50 yards on each side of this straight line yearly for dead deer. No more dead deer counts on my properety for the last few years.

We are fortunate to have a real scientific and accurate system, it works better than any mandatory deer count no matter who is telling you that it is or not.

I also posted that I have discussed this subject with field biologist from several differant states that had mandatory deer check in. They all agreed, Michigan had it right but reguested that I do not quote them.
 

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Another valuable post, Whit. Thanx.

And, I admired your insightful observation that not understanding the process is not sufficient to reason to declare it invalid.

We can hope that such postings as yours may eventually convince an increasing number of the shoot-from-the-lip critics that their irresponsible opinion-enemas do far more harm than good.

I believe...firmly...that there are staffers within the Wildlife Division of the MDNR who are sufficiently educated, adequatley trained, and sincerely motivated to give us competent management of the deer resource.

That's not to say that mistakes and misjudgements are not made. It would be unwise to believe otherwise. But, I also think that with the status of Michigan's deer herd being so visible and effecting so many competing constituencies that even the new-hires within the department quickly grasp that deer issues are really sensitive.....so dot your i's and cross your t's.....cause somebody out there is always going to criticize.

That alone gives us....ah, stockholders, if you will....some reassurance that the management of the company will be prudent with the assetts.
 

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Great post Whit,but after living in Wisconsin or 3 years I think that our system is not what it should be. I liked what I saw in Wisconsin and I think they have a better way of knowing how many deer were taken.
 

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Whit:

You seem more knowledgable than most regarding Michigan deer population.

Perhaps you can help me.

Do you know if the MDNR releases the actual data they obtain regarding scientific estimating? I have seen Deer harvest info but don't believe I have ever seen the other data you reference in your post.

As you may be aware, there is a great debate as to what our deer population estimation really is.

I would enjoy reviewing our raw data and further understanding how our MDNR uses this data to determine our deer population.

Any suggestions?

thanks,

Bart
 

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Discussion Starter #6
bart2006 said:
Whit:

You seem more knowledgable than most regarding Michigan deer population.
Bart

Bart,
Trust me, this is NOT the case at all. I can name several other members who put me into the corner with the rest of the dunces when it comes to knowledge of Michigan's deer population.

I woiuld suspect that what we see is not the raw data, but rather the estimates based on statistical parameters that have been developed over many years of analysis.
 
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We should ask ourselves this question. What are we going to do once we have the deer density estimate. How is that estimate going to help us in making future deer management decisions. Will it really help or are you only interested in knowing numbers, (a normal human trait) and nothing else.

What if you were in the northern UP following a severe winter, Would you take into consideration the the previous falls deer density estimate or the severity of the recent winter in determining the number of antlerless permits to issue for the upcoming hunting seasons?

What if you were in the northern lower and the deer density estimate indicated that there were only 30 deer per square mile, (with the DNR goal being 35) in your area and there were several wide spread browse surveys that showed extensive habitat deer browsing damage throughout your area, would you eliminate or have an intensive antlerless permit increase?

The point being made is, "knowing the number of deer that we have statewide or locally is of little concern, (unless the deer density is obscene) when you are making deer management decisions".

Think about it, when you heared in the past from our DNR that the deer herd numbers were up, you got excited, while the opposite was true when we heared that the numbers dropped. Keep thinking back, was there a differance in your hunting experience those years,wheter the estimate was high or low? Not really was it?

It is only a number and not relevant when making good deer management decisions.
 

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Ed Spin04 said:
The winter pellet count does work, but no better than the pellet counter. You do not find as much support from DNR personnel for this antiquated method.
AMEN!

By the way, I have taken several statistics courses and fully understand the mathematic priniciples behind its uses. I believe the real issue here is that Michigan has not moved forward in its use of newer technology and ideas because that may actually cost a dollar or two. I also believe the current NRC underestimated hunter reactions to their current policies and they are now just catching up with trying to actually communicate to the user groups.

Dan
 

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Whit:

Wouldn't it be great to have a group represented by the average hunter that evaluates the raw data that we pay the DNR to develop? This way, when the DNR asks for our opinion we can respond from a more educated perspective.

I have requested this data but have had no luck even getting a response.

Do you know anyone at a senior level with the MDNR that might entertain a meeting with me?

Ed: let's not wait until we have the estimates. Let's get the real data then we will be more prepared to respond to the estimates....

Bart
 

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Discussion Starter #10
bart2006 said:
Whit:
Do you know anyone at a senior level with the MDNR that might entertain a meeting with me?
Bart
Nope! I can't help you out there. I'd urge you to find out who the resident DNR deer biologiist is in your area. Hell, I don't even know who mine is!!!! :lol:. That's one of my New Year's Resolutions for 2006.....get to know who he or she is.

Ed Spin, [email protected], NorthJeff, Boehr, or others may be able to help you out.
 
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Bart, are you kdding about an informed statistics hunter group being allowed to evaluate DNR data. Which fudge factors would you put into the equation? You must know our DNR has their agenda and their own way of getting numbers that satisfy them.

Example, I was told by a MDNR top official, you all know him, and several field biologists that we should take at least one doe for every buck taken and throughout the state. When asked, "Even the northern UP following a harsh winter, even without any restraint in the harvesting of young bucks"? Yes, was their answer and even the northern UP and yearly. I asked, "Where does this deer management directive come from"? I was told that the MDNR has a model in lansing, (I didn't think it was possible coming from the UP) developed by experts that suggest this harvest method. So much for MDNR scientific statistical harvest data, or is it fudge? Next time you talk to a MDNR field biologist, ask them this question.

We hunters would never agree with the DNR on any statistical outcome, for we have no agenda except the truth.

Bart, we would have better luck asking MDNR officials to sacrifice their oldest male child.
 

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Ed:

Dead serious. Of course I know our DNR well. Sooner or later the average hunter is going to call their bluff. If necessary, I will implement a publicity campaign to ensure that the raw data is made public for the very people who pay for it.

I am intrigued that MDNR has a model in Lansing. Tells me they had to build it out of something other than Mackinaw fudge.

I was given the name of my local Field Biologist this morning. I am hoping she only has girls.....

Thanks, guys. I really appreciate your help.

Bart
 
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