Wild Deer Culling Research pt.2 - The Comanche Ranch Study

We're picking up where our last episode left off on the topic of deer culling for genetic improvement. Donnie Draeger is joining us to discuss the iconic Comanche Ranch high-fence culling study that went to even greater extremes to test whether deer herd population genetics can be improved. He and Bronson discuss the logistics of conducting a study of this scale, the results, and what contributed to the challenges they face in improving genetic quality of bucks.

You can read more on the the actual study here:  https://wildlife.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/wmon.70013

Transcript

Intro & Guest Welcome

Moriah Boggess 0:02

Welcome to Wildlife Investments, where we discuss wildlife research, habitat, hunting, and land management with our panel of leading resource managers. Wildlife Investments, resource management by scientists. Hey y'all, August 29th, Raymond, Mississippi. We are holding our Deer Management Academy. You're not going to want to miss this education-filled day on everything from the basics of deer biology to nutrition, diet selection, property layout, how to make habitat management decisions on your property to reach its fullest potential. We're going to cover it all so that you can manage your property like we manage ours. Go to our website, click on the education events tab, and you'll be able to buy tickets there. And if you hurry, you can probably still get a ticket for the social event we're holding the evening before. It's going to be a small crowd. We can all get to know one another. Talk management, it's going to be a good time. So we hope to see you this August.

Part 1 Recap & Study Goals

Dr. Bronson Strickland 1:04

Okay, welcome back everyone to the Wildlife Investments podcast. And we are today, we've got a very special guest who needs no introduction. Actually, need a pretty pretty big introduction, but a little reminder: this is part two of uh three three-part episodes, three episodes that we're gonna do on the calling experiment that was conducted at the Caesar Clayburgh Wildlife Research Institute at Texas AM and with the King Ranch and the Comanche Ranch. The first episode was recorded with Mick Hellixon, and in that in that episode, we talked about his study design, how they conducted the study, the lack of any results, and kind of the shortcomings, and kind of concluded that with some recommendations. If we're going to do it again, these are the steps he would recommend be taken. And so that is what we are going to do today with what we're calling the Comanche Ranch Study. And to help me navigate this and kind of explain the justification and the logistics and so forth, we're we're joined by Donnie Draeger. Donnie, thank you for coming, taking the time. Pleasure. Good to see you again. And gosh, man, we did uh an episode on this probably 2018. It was right at the conclusion of the field.

Donnie Draeger 2:37

Yeah.

Dr. Bronson Strickland 2:39

And so at that point, you you were kind of bringing everyone up to speed. The numbers had not been crunched officially yet, but we kind of the what you could see in the field was that there wasn't any compelling result at the time. And I think that's what we talked about at that point. But the reason we are revisiting this is that that has now been published. And so we ran all the stats, got the peer review, and so that is out there and published, and so we wanted to to revisit the experiment again. So that is that's what we're gonna do. And I guess I'll start with

How the Comanche Ranch Study Was Born

Dr. Bronson Strickland 3:18

some of the things that Mick suggested be the next step. And so one of the big issues with the King Ranch study was dispersal. And so that was a low-fenced or unfenced study areas, and so bucks were going on and off the different treatment areas, and so that was that was a a big problem. And and also a recommendation was to evaluate different culling intensities. And so Mick began at the yearling age class, but in this study it was to evaluate starting at the yearling age class, but a moderate level treatment starting at at three and a half, and then also having a control. And so I know Donnie that you were very adamant about having a separate control pasture for this study. And so all the treatment areas were enclosed. The moderate area was about 85%, Donnie. So I guess there could have been a few bucks moving out, but practically speaking, it was completely very very little.

Donnie Draeger 4:27

I mean, we we may have tracked one or two over the you know 13, 14 year study.

Dr. Bronson Strickland 4:32

So barely. Yeah, possible but very unlikely. Sufficient to say, Donnie, near Eagle Pass, Texas? Sure. Yeah, Maverick, Demet County, Texas, you know, southwest of San Antonio, about two and a half hours.

Eagle Pass vs. Kingsville: Habitat & Rainfall

Dr. Bronson Strickland 4:47

How would you, Donnie, to I I know that the differences are very obvious to you because you live in that area. What are kind of some general differences in in habitat in in Eagle Pass as compared to to Kingsville, where the King Ranch is at?

Donnie Draeger 5:04

Well, it's a pretty stark contrast because the where Kingsville and where Hellikson did his study is, you know, they get pretty predictable rainfall in the average year, and they're a grass-driven prairie ecosystem and Gulf Prairie ecosystem with large, you know, with some obviously brush and motts and and scattered about and certainly in the creeks. Where we're more of a brush land dominant mesquite environment that is xeric or very dry and has, you know, there are very few trees, if you will, from traditional trees, you'll get a few elms and a few live oaks in the creeks, but everything's brush related, acacias, mesquite, legumes, all that stuff. So and and very very variable on rainfall. You know, you can have 30 inches one year and eight inches the next. So I'd say that's the that's one of the major uh probably the mate the major thing, the major difference between the two ecosystems.

Dr. Bronson Strickland 6:07

Going way back, if you even remember, how did the study begin in terms of whose idea was it? Who twisted your arm, or were you doing the arm twisting? How did it come about?

Donnie Draeger 6:18

I was doing the arm twisting because we were already involved in Caesar Clayburgh with a with the another study that you're very familiar with and is our supplemental feed and density and and native vegetation study, the Comanche Faith study is what that one was called. Also published, peer-reviewed, and has a book about that, but plug that later. We uh so we were involved in that. I was Mick and just, you know, as you you're one of my friends, Mick was one of my friends from the Faith Ranch days. So, you know, Mick and I kept in touch about how he was doing on the the King Ranch study, and he was telling me, okay, yeah, this is a problem, this is what we're seeing. And it just kind of started the juices flowing and the soup cooking. I and I just couldn't get it out of my head. So I went to the boss, the owner of the property, and said, Hey, what do you think of you know, kind of doing the next step of what they did? But and we decided to do that while the King Ranch was still actively doing their study. So we had started our the communications with Texas Parks of Wildlife for permits, with AM Kingsville, Charlie DeYoung, getting, you know, kind of being our head head researcher. So we started all that before King Ranch had even concluded their study. And so it was really pretty. I want to say, even at one point, we may have been going at the same time for a a year or two. But anyway, so we we bounced off with what we called what we just kind of considered the new and improved way to take it to the next level. And and really to the point that the way, and we'll describe this as we get in it, but the way I wanted to run this study is I wanted to I wanted a definitive line drawn in the sand is how I describe it. This study, we knew going into it, not everybody could achieve what we were about to attempt, or even attempt what we were about to do. So what we but we wanted to go at a degree that was so that no one would question the intensity of the study. And and and by doing that, we also realized no one would probably be able to replicate it. But that's okay, because the way I thought about it is either it works at this level or it doesn't. And if it works, great. Then we can kind of back down the gas pedal and figure out where people can jump on board the train. Where it doesn't work at this level, then there's your line in the sand. Let's stop talking about it. This is not an achievable thing. So that was really kind of the genesis of both my boss and I talking about, well, yeah, let's just go, let's just go figure, let's just go put a dot on the map or you know, a dot on the board and see if see what happened.

Dr. Bronson Strickland 8:58

If it doesn't work with this study design, in other words, if it doesn't work with the methods you employed, it's not gonna work. Yes. Yeah. Okay. And and I guess, you know, just a wild, wild guess here. What was it? Probably a couple thousand dollars it may have cost to do a study like this.

Donnie Draeger 9:18

I'm under strict, strict rules not to talk about that aspect of it. But uh, yeah. Again, another reason I seriously doubt this study will be will be replicated. I mean, I I like to say that it's the most intense culling study ever done on white free-ranging white-tailed deer. I believe that's a fair statement, and I also believe that it'll never be replicated at the intensity we did.

Dr. Bronson Strickland 9:49

Yep. Agree 100%. So we'll

Study Design: Three Treatments Explained

Dr. Bronson Strickland 9:53

get into it now. And Donnie, what what I've been doing, I've just been I want to make sure everybody gets credit involved with the study and the title of it and so forth, if people want to look it up. And and I think Mariah, maybe we could put a link in the show notes to it. We as we didn't to the monograph. Yeah. Okay. But this particular chapter in that monograph, the title is Influence of Selective Harvest on Whitetailed Deer, Antler Phenotype, and population demographics in experimental, high fenced populations. Yeah, we like to keep our titles real simple and easy to understand.

Donnie Draeger 10:30

So I clearly did not write that. That was uh well beyond, I don't even know what that means, much less your viewers. So now we're gonna be able to do that. That's a Charlie De Young title, right?

Dr. Bronson Strickland 10:39

Yeah, that was a Charlie De Young title. Good for Charlie. The authors, of course, Donnie Drager of the Comanche Ranch, Charlie De Young, Masa Onishi, Randy DeYoung, David Wester, David Navarro, and Dave Hewitt, all of the Caesar Clayburgh Wildlife Research Institute at Texas AM Kingsville, myself from Mississippi State, and Alan Kane from Texas Parks and Wildlife Department. There we go. Okay, Donnie. So we're gonna go through real quick the the treatments. So there's there's two treatments under control. Okay. The intensive treatment, and I I thought this was very bold, and I know you intended for it to be bold. But in your country, when you're calling yearlings that have less than six points, you're gonna call a lot of yearling bucks. And that was the point. Yeah.

Donnie Draeger 11:37

Yeah. Yeah. But it was, and and let's be clear about that. The intensive is is there's about a 3,500-acre about yeah, 3,500 acre pasture, 3,000 somewhere right in there. And this was a this is kind of a cur wildlife management, an ode to or a nod to the cur wildlife management data from the 70s and 80s. And it and to the point that in the beginning we did have some cur wildlife management guys involved in the study design. And this was their recommendation. So we at Comanche Charlie, myself, and my boss kind of liked the moderate idea, but they they wanted to step it up a notch, and this certainly does. And and like you're saying, those anything six points, anything less than six points was called as a year.

Dr. Bronson Strickland 12:30

And uh at two, anything less than eight points, again, very aggressive. At three and a half, anything less than nine points, the same for four and a half, anything less than nine points. And then Donnie, y'all move to Boone and Crockett at at maturity. And so your your average down there, I know depending on what past you're in, rainfall that year, but probably somewhere between 125 and 130 is a general regional average.

Donnie Draeger 13:01

I mean, it yeah, it can bounce above that a little bit. I just like to say 130 as an average, average year, average in Cheerbuck.

Dr. Bronson Strickland 13:08

So with with this criterion, you are on the right side of the bell curve. You're removing most of the deer are going to fall below 145 gross spoon and crocket. So that is the that is the intensive treatment. Moderate is essentially ignoring those those really young deer, the yearlings and the two-year-olds, giving them the benefit of the doubt, whether they were born in a drought year, born to an inexperienced mother, et cetera, et cetera. But you're you're giving them a couple years to what we think more reliably express their genetic potential. And so the calling there began at three and a half with the with the same criteria as as you had in the intensive. So at three and a half, less than nine points was called. At four and a half, less than nine points was called, and then the same at five and a half plus less than 145 gross boot and crockett score. And then yeah, do we we have the control up here? Yeah. So the control is just simply there's no culling whatsoever, but you're capture, capturing, and measuring. Okay, Donnie, go through please the

Moriah Boggess 14:25

So just real quick on the control for a clarifying question. Was there any hunting, non-culling, just any random hunting in the control?

Donnie Draeger 14:32

No, it's a great question. And there was there was I wouldn't say random, a very light sport or recreational hunting, is what I'd call it, and all three three control, moderate, and and intensive. Okay. So we kept the ranch running like a wildlife and like a hunting ranch uh in that process. But we're not a commercial hunting operation. We run low numbers, row low, low numbers of hunters. So it was it was not impactful to the study. And when we did kill deer in the intense in any one of those areas, they all got put into the database.

Dr. Bronson Strickland 15:08

I'm I'm glad you you pointed that out. And I reread that part last night. And and yeah, Donnie, exactly right. Very few of those bucks, and and what we did is we added them back in. So there's no influence of those deer that are affecting the results. So yep. Okay,

Helicopter Capture vs. Hunter Harvest

Dr. Bronson Strickland 15:27

Donnie, with Mick, the selection was via hunter. The selection was with the rifle. Mick was guiding typically most of those. So they are making decisions in real time on the hoof, assessing the age and then applying the antler criteria and making a harvest decision. So if you don't mind, go through real quick how y'all took it again to that next level of taking hunter error and assessment out of the equation. Right, yeah.

Donnie Draeger 15:58

And we knew that was a that was a weakness, if you will, in quotes, of the King Ranch study, you know, and Mick Mick expressed that. So we decided with the advent of helicopters, and you know, there was this thing called Triple T or TTP in the state of Texas, and that's trap transport and translocator, trap transport and process. There's some permits that Parks and Wildlife gives. So there was this already methodology of going out and capturing deer and doing something with them, you know, wild deer grabbing via helicopter net guns. So we would use two capture helicopters and one transfer, transport helicopter, the traps, the the excuse, sorry, the capture helicopters would be either R-22s or R-44s, and they would fly around and the first buck they'd see, they were, they were told to just grab it and and try to net gun that, and they, you know, get it on the ground, tie it up, and then the transport helicopter would come over and and tie a rope around the legs and bring it to a process a central processing point within that area that we were working in. And that would just happen all day long, all day long. And and we and that's and then once it got on the ground into the central processing area, we had Charlie D. Young there, who uh legitimately, and but uh I don't think there's an argument, has aged more live deer than anyone else on the planet. And they want it's not even a close contest. I mean, he's into tens of thousands by now. And so he would age it right then while people are working on it. We're we're uh pulling hair, pulling, we're doing a little tissue sample and ear knots, we're we're scoring the antlers, we're you know, we may take an antler sample, we may take hair samples, all those things were happening furiously as as Charlie was also aging it. And then once we knew the age from Charlie and we had a score, or you know, and on the younger deal, we didn't even need a score, we just counted points. We would decide whether that animal was euthanized right there, or we'd if it was not and it passed the culling criteria, it was big enough to get let go, then we would uh put a pit tag, a subcutaneous little bitty chip that you couldn't see, you couldn't see at all. It just sat right in the base of the ear underneath the skin. And that would be if we ever caught it again, we could wave a wand over that and it would pop up this unique ID number, and we'd know that we'd not only we know that we caught it, but we could look that deer up.

Dr. Bronson Strickland 18:36

And did that always work with the unique ID numbers?

Donnie Draeger 18:41

No, that was a oh, you know the answer to that, and that was a leading question. I love it. That was turned into a bit of chaos because we were using a company to go unnamed out of Canada for these sub for these pit tag readers, and unbeknownst to us, they had sent us double pit tag. Uh actually, instead of each one having a unique number, some of them were the exact same number. So a bane of my existence was about four years into the study, or maybe three, or somewhere in there, we realized this, and we realized we were tagging different deer with the exact same ID. We knew that because, like, one ID, this unique ID would be in the control pasture, and 20 miles away on the ranch would be the exact same ID of another deer in the moderate pasture. We're like, there's no way that's the same deer, that's impossible. And so I started piecing the mouth together, and I spent months on that database working it all out and getting it figured out. But and then also the other part of this, those things get damaged if a buck fights and an antler hits right there, it breaks. There's just natural sometimes. The guys think they put it in, they they push it all the way through. There is it's humans doing human things, and we make mistakes, and that's that's part of it. But you know, we have a very large database that weeds, you know, that kind of dilutes a lot of that stuff out, and so that I still feel very strongly on the strength of the database and what our results are.

Dr. Bronson Strickland 20:13

Oh, yeah, 100%. I I just brought that up because uh I know it was such a pleasant memory for you at the time. Man, you got me drinking. And then the and then the days literally you and I lost. I think reconciling all those numbers, if you remember.

Donnie Draeger 20:30

Yes, because you were part of that and it went on for years. It never really ended until right when we were finished with the monograph, and Charlie was doing that. I mean, it went on for years. I it let's hope that guy in Canada who did that never I never meet him face to face, because that took some years off my life.

Dr. Bronson Strickland 20:52

Well, uh Donnie, of course, you've you've I don't know how many weeks, if you put all the different captures together, how many months, but so it's second nature to you. But for those that have never been a part of one of these, it it is an absolute sight to behold at any given time, seeing two or three helicopters moving in the air, hearing the net guns go off, and then the transport helicopter brings a deer, and that's kind of what we see there. They're dropping a deer off, Charlie's gonna age it, and then uh all the measurements will take place. But at that point there, that is where where Mick would make an assessment, and the hunter with a rifle make up a culling decision. That decision was made right here. So they have a much better, more reliable estimate of the age and can literally measure the antlers. And so this is kind of the gold standard for this type of field research. This is kind of the gold standard and being as accurate as possible for making a culling decision. And I just threw that one in there because man, that was a good one. That was the day I. I was there, Donnie. Oh yeah. He's a good deer.

Donnie Draeger 22:03

He's a good boy.

Dr. Bronson Strickland 22:05

Okay. We don't need to spend any time with that. But I didn't know if you were going to talk about the pit tags. I was just going to review that. So yeah, just a way rather than having ear tags all in the the box on the in the study areas, it was just a way to kind of cryptically mark every single deer and know if he was recaptured later. Okay, I I do want to spend a little bit of

What Success Should Look Like: The Theory

Dr. Bronson Strickland 22:27

time here, and this is the theory. What did this with Mick with the King Ranch data? Want to just demonstrate to people that this is what you should see in the data. Number one, if what you are doing in the field is working, and then ultimately if culling is changing the genetic makeup of your deer herd. So step one, this may sound silly, but you have to demonstrate this with the data, or you cannot possibly expect to have a result. You have to ensure that the culled deer are on average have smaller antlers than your standing crop. So you've got to be sure that you are consistent enough with the bucks that are that are being removed on at on average, they have a lot smaller antlers than the standing crop. And so that's just what we're demonstrating here is that the standing crop, that is gonna be the population for each age class. And notice that the the antler trait, in this case, is Boone and Crockett score, the antler trait of the alive animals, the unculled animals, is a lot greater than the animals that are removed. So that's step one. If you can't do this, you don't need to do the study. Step two is uh kind of a term Donnie and I throw around a lot. It's called sculpting the cohort. And that is basically once you were done, you know for a fact you you are removing below average animals. Now you have got to make sure you did you remove the right animals and you did it with enough intensity, enough frequency, that you have shifted the the average antler size from the pre-call antler size to the post-call antler size. And so all this simply means is you have an average number. Let's just say for for ease of description here, you've got a Boone and Crockett score of 100. You've got to remove enough of those sub-100 Boon and Crockett scores to actually improve the mean, to make the moon the mean of the standing crop or that population greater after the culling event. That's what we would expect to see. And then finally, the result over time, if this is working, and notice I have a lot of years, I've got 20 years down here on the x-axis, is that, and I've got yearlings displayed here, and I've got mature bucks displayed here. Is that over time you should see the average antler size of the population slowly getting better and better and better? That's the theory. That's what we expect to see, that's what you'd want to see if it's working.

The Results: No Genetic Change

Dr. Bronson Strickland 25:21

And now we're gonna move to the to the actual results. And so here is our sculpting the cohort, so to speak. And what is plotted here, Donnie, is just the the average antler size of the bucks that y'all removed, and then the average antler size of the ones that were released. And those were significantly different, big difference between those two, those two populations. And notice in the intensive treatment that is starting at, again, the yearling age class, and the moderate treatment that begins at three and a half. But what is consistent across both of those is that the called deer were indeed a lot smaller than the average population. So that part works. You got to fulfill that. And now I'm gonna go through each age class, one, two, three, four, and five. Now here are the actual results. So before it was the theory, now we've got the actual results. And again, we the the study removed enough deer. The number of bucks, the intensity of removal, it changed the the standing crop in real time. But what is now is happening over time. So that that's the real measure if this is working. So you'll see at the bottom there, Donnie. I grouped years because you have so much annual variation down there. I didn't want to just examine one particular year. So I have 2006, 7, and 8 grouped, 2011, 12, 13 grouped, 2016, 17, 18 grouped. And those are the averages there, average Boone Crockett score on the left yearling. So we're comparing the control to the moderate treatment to the intensive treatment over time. And so what you want to look at is compare the left side of each graph to the right side of each graph, and you'll see with the yearlings, there was no change in the Boone and Crockett score. Your control took off for whatever reason.

Donnie Draeger 27:30

Yeah, so there's there's it depends on how if you want me to dive into this right now, but there's a theory on why we think that for the yearlings specifically, why we think that control took off, and or and there's really no change, or there's there is a reduction from 11 2011-13 to 2016-18 a little bit, but there's statistically speaking, there's really just no change in the yearling size for moderate and intensive, even though control, control just went. Now, is that rainfall got a little better in that portion of the world? That's probably it. But there's some other stuff that I think is probably now that I think of it, it's probably more appropriate to talk about why we stopped the study on our negative feedback loop. And so we'll hold off on that and just tease it with that. But as we get into that. So sorry, Kyrie.

Dr. Bronson Strickland 28:24

Well, pretty much the same result. And and yeah, Donnie, you you brought up a really good point. If you wanted to split hairs, there may be an inch or two difference in some of these results. Sometimes that the treatment's greater, sometimes sometimes it went down. But the thing we have to keep in mind here is is there a practical difference? Is there enough of a difference to motivate you to engage in, you know, 10 years of culling, for example, to get a trivial result, if any result at all. And so when we look at the two and a half there, we're kind of seeing, yeah, there may be an inch or two difference, but it it's not enough to motivate you to change your management plan. Same thing at three and four. Again, just notice when you look at whether it be three-year-olds or the four-year-olds, compare the average antler size at the end of the study, 2016 to 2018, to where it began, 2006 to 2008, and you're talking a trivial amount of difference there. Literally an inch or two, if there's even an inch or two difference. And then to me, what's most important is our mature bucks. And so are we producing any more trophies at all? And notice here with five and a half plus, again, there's there's no difference. So no change. So we had culling constantly. And Donnie, here's where we can jump in with

The Negative Feedback Loop & Near-Buck Extinction

Dr. Bronson Strickland 29:58

why the culling stopped. We ought to tell people that culling was actively occurring from 2006 to 2012. And Donnie, you can jump in here and say, why did it stop at 2012?

Donnie Draeger 30:14

Let me back up and throw a few numbers at the audience so they just understand the scope of the study. I mean, through 2006 to 2018, we have 10,976 captures. That is now that's that's a lot of that's the lines of data we have. That's the in every one of those is a line of data, you know, with all this data faced into it. You kind of have to picture this matrix, if you will, of this giant thing that we were working off of and continuing to build every year. So 10,000, so just shy of 11,000 captures in that time frame. That incorporated inside that number, that 11,000 number, there's 2,937 individual bucks. There are also 2,510 recaptures. And out of that, there were a total calls on all both both treatment areas are 1,333. And we only called for seven years, and we're going to jump into that reason why, it's where you're going for. And then we may not get into this, but I like to throw this number out. That we assigned, we had an assigned offspring for sires to offsprings for 963 fonts or or or captured deer that that we knew their sire. That's an amazing thing for a free-ranging deer herd to have. We did that through the DNA analysis or DNA samples. And to have a teeny bit more moderate area, we called that 18,000 acres was the moderate area. We called 908 bucks in seven years. Do the math real quick, right? That's heavy. But then you go to the intensive, that 3,000 acres, we called 375 bucks in in seven years. And the yearling AIDS class specifically had a cull rate of 94%. So only 6% of yearlings caught were released. That's as no one can complain about the intensity. It it to the point now we have people complaining, oh, you went too hard. You went too too hard on, you know. Well, you can't have it both ways. I mean, but anyway, we'll get into that. A good little real-world thing for people to understand what happened in that 3,000 acres of the intensity pasture. Before we started in 2006, I flew a helicopter survey in there and I counted 73 bucks, individual bucks, unique bucks flying around, you know, doing a regular traditional survey. In 2012, same survey, same route, same everything. I counted nine bucks. And that's why we started. That's why really, and it was Bronson, it was you that brought this up to our attention. We had we had created a negative feedback loop that I spoke of shortly earlier. So what we had, we killed so many bucks in both the yearling and all the AIDS classes in the intensive pasture that all the way down to the yearlings, that we skewed the buck mill ratio. The buckler ratio starting in there was about one to one, one to one point find, maybe one to two on a really heavy year. But and then we moved that all the way to one to six, one to seven, somewhere in that ballpark. And what happened is, and there's just a sheer, so few bucks left after six, six, seven years of culling that they literally could not cover and breed all the does in the first ester cycle. So a significant amount of does went to the second ester cycle. That in in turn creates late-born fawns, probably a term that your audience is familiar with. And those late born fawns don't have the same amount of time. They're born 28 days later, usually, they don't have the same amount of time to add body growth, to add, and then push that excess into antlers. They're more often than not, they're spikes than they are fork antlers. And then they get judged that first coming year by being caught and being judged the same as everybody else does. They have to have six points or more, and they get killed. They get they get killed. So in that that little circle created what when when those second generated and third generation late born fawns were being killed, even though they were sired by a and I'm doing this in air quotes for the audience listening, a superior sire because he's made it through calling and he's gent he has a much higher average than a Crackett score. Even though they're sired by a better sire, they are not performing uh antler-wise because they're they have too many cards stacked against them early in life. So they're called. That then leads to what we coined, you and I like to coin uh that that that led to what we call local extinction of the bucker. You know, you're approaching local extinction of your bucker. So you pointed that out through your statistical analysis, and it became very clear. So in year seven, that was a long-winded way of saying we pulled the plug on the culling, and then from that point forward, the rest of the time, six years more, we we just captured and treated kind of like everything, like the control, capture, measure, release. And we wanted to see if there was a delayed effect as those deer got, you know, those yearlings got to six, seven, you know, five, six, seven years old, if they would be able, if they would express their superior genetics that supposedly their sires passed on to.

Dr. Bronson Strickland 35:50

Well, you you certainly, the the few bucks that remained in the intensive treatment after all those years, you absolutely had a a buck population of phenotypically, anyway, phenotypically superior sires. And so that that to me is what's amazing, even in the uh intensive treatment, with all those, there's very few of them, but the few that are there are really, really good. And we look at the result there, and there's there's no change in average antler size. So this might be rehashing a little bit, Donnie, but yeah, I I anticipated that as well. Did you call enough bucks? Yes. Yeah, absolutely called enough. Yeah, yeah, yeah. In the intensive treatment, so Donnie, you were talking about at the yearling age class, one year or some years, it was 90% or more. If you looked at all the age classes over all of the years, the average was 48%. So essentially half of those blocks are getting cold. And then in your moderate treatment, it is still high, but it was just 20% at night.

Donnie Draeger 36:59

Yeah, and I have a little a little color to add on that moderate treatment. You know, we were just 18,000 acres of the ranch and we were actively hunting it as a trophy management and trophy, trophy hunting that place. And so we're spending time out there like anybody else does, sitting in blinds and and you know, recording deer and watching deer and all that stuff. And I remember seeing like most bucks that came into the feeders and and that you were viewing hadn't had a little ear notch on them. So which means that was kind of our way of going, oh yeah, you pull up the binoculars. Oh, he's been caught. You know, you could tell that ear notch on the bottom part. And so I can see that on the vast majority of bucks that were coming in, but yet when we actually dug into the data and got empirical look at the data, we only called 19%. And we didn't, well, I'm getting ahead of us, you know where I'm going with that. We we didn't really change the standing crop on that, and that was shocking to me. So I may have jumped ahead a little bit on you, but uh still just some color to add to that.

Moriah Boggess 38:06

Did um I know this is this is what you were hinting at there, Donnie, but if if 19% was cold, obviously a much larger percentage was caught in in was there was a decision made. Did you guys ever, from your traditional population surveys, did you all ever make an estimate of what percentage of the population was examined each year for that that calling criteria?

Donnie Draeger 38:31

Yeah, actually we have that data through Gary White, Colorado State, did that. What's that? Help me, Bronson. That's called capture. Yeah, the program's called capture, right? So and we have that. Do not get me trying to jump that off the top of my head. I don't have that, but we could it was basically think of it if for the people who who are scientists in it or biologists in the office, think of it as a giant Lincoln Peterson marker capture study. And from that, that Gary White in Colorado has done this amazing program called Capture. It's really complicated and huge, and it's way beyond my little brain can handle, but he's he knows how to do it. He could he could give us a true estimate of how many, what percent of the deer herd we got our hands on. And and by default, you also then would know how much how many deer are in that area. So so we had those numbers. Those are reported in the monograph, the J Journal of Wildlife Management monograph, they're in there. They're a uh it's it and so you can you could dig into that if you wanted. But I can't remember off the top of my head, I apologize.

Dr. Bronson Strickland 39:39

Yeah, I uh I don't rem remember the specific numbers either, Mariah, but but yeah, Gary White crunched the numbers, and so for for every treatment we got uh uh population estimate every single year. And that's how we calculated the the calling rate was we know how many were removed relative to how many were alive that year. Yeah.

How Often Do Bucks Switch Cull Status?

Dr. Bronson Strickland 40:02

Okay, Donnie. Something that that we did, and and by we, uh it wasn't me and it wasn't you, but some some smart people developed this calling state transition frequency. And I I think this was pretty brilliant way to look at this. And essentially what this is, we talked about it some for the King Ranch study as well, is how often or how how frequently can a buck switch from if he was designated as a cull antlers this year, would he be a non-cull the following year or vice versa? And y'all were able to track this through your control pasture of knowing because you're capturing them and and you're releasing them, you're knowing how often they're switching. And so for

Donnie Draeger 40:53

not just control pasture, we we were able to do that on on the when when you had a deer that you could also have a deer that was a trophy that went to a call and the treatment pastures, and that would count into that database as well. Sorry to interrupt, but yeah.

Dr. Bronson Strickland 41:12

And from the treatment pastures, once you stopped calling, you got that information as well.

Donnie Draeger 41:17

Yeah, a lot of yeah, exactly. Yeah. And let me add some color to this as well, because I have my graph open on my other computer here and I'm looking at it. From percent that changed from call to trophy, from yearling to a two-year-old, right? And so let's let's let's define that in real world sense. That means that in a yearling it had five points, it had five points or less, meaning it was a call, right? And then how many of those went ahead and changed to a trophy the very next year, which would mean it would have eight uh nine points or more. Understand? Okay, that makes sense. And then at two-year-olds, they were trophies, meaning they had nine points or more. 68%. And remember, we for lack of a better term, we kind of arbitrarily picked these these point numbers, but it was it wasn't necessarily arbitrary, but it was also again hinged on some of the work that the Kerr did, Kerr Wildlife Management Area in Kerrville, Texas did. So that it wasn't, I say arbitrary, it really wasn't. We we did some work off of that. But another one that kind of the other end of the spectrum at five and a half and plus, all of those grouped together, the the percent that went from coal to trophy, uh, from meaning that were below or 144 and 7.8 or below as a call or 145 and up, only 14% changed to that at at in in the trophy. So as you go down that your age, as you go up in age classes, that variability does shrink over time from switching call to trophy. There was there seemed to be a more consistent variability, and not a lot, a lot of variability, and more consistent going from trophy to call. If you analyze this data and just kind of lumped them all together, you would really get just a 33% of your bucks would go from trophy to call. And it was pretty consistent across the age classes.

Moriah Boggess 43:39

That frequency, Donnie, you said of from going from yearling to two and a half from coal to keep. Did you guys look at that that rate of change when you were in the middle of that negative feedback loop? Could you see a measurable increase in that?

Donnie Draeger 43:54

No, we didn't really dive into the data in that regard until after it was pretty much. I don't think we did, did we, Bronson? I don't think we die did this analysis until we were done with the study and and kind of you know we you know we're still a fully operational working ranch, and these were uh you know several days a year, or you know, four to six days a year we were doing these captures, and the rest of the time we're we're doing ranch and hunting and all the stuff that these ranches do down there, and and so I didn't have a lot of spare time to just dig into the data to the point to this point until I really started doing some talks on it, and then we got more serious about getting the the the monograph out to JWM.

Why It Failed: Heritability, Rainfall & the Doe Problem

Dr. Bronson Strickland 44:41

Well, it is it's just another good example, and we've talked about this numerous times, but when you're using a a trait, antlers, that is so influenced by the environment, you can see how it becomes very inefficient to even possibly make any genetic change. So you you don't have a very reliable signal to to judge you know the quality or quote the the genetic quality of the animal. And that's again that that that makes this process so problematic. Whether you're in the the east or in South Texas or wherever you're at, that that's always gonna be an issue.

Donnie Draeger 45:21

Yeah, and if you you know, if you talk to Randy DeYoung on the next one, you're you're gonna have that data. I mean, I have the data as well of kind of how how much heritability is in a in that her, you know, in that deer versus how much is permanent environmental effects, how much is just unknown factors. The val if you broke that out in a pie chart, unknown effects are huge. We don't even know what we don't know. So that that's what that's an interesting thing. I'll let Randy dive into that. He'll be much better at it than me.

Dr. Bronson Strickland 45:58

So uh I I kind of put this together about, you know, the recommendations from from Mick and and did you fulfill it with this study? Was the calling rate intensive enough? And we we've covered that. Well, when the buck population declined 88% in the intensive treatment, I'd say that's that's pretty intense. And and here, Donnie, is that sex ratio for that negative feedback loop you were talking about? It changed from 1.2 to greater than five, depending on the year. Yeah, it was up there on the high years. Did culling change average antler size of the standing crop? Yes. So we've already shown those graphs. They were significantly different. So that the the number and the type of buck removed, what was sufficient? During the culling period, yes, the sires were larger. So what remained after these culling events, there were larger than average sires relative to the four.

Donnie Draeger 46:58

To put a number on that, I believe it was about a in in the intensive past year, it was about a 20-inch Boonie Crockett score difference. I mean, I'm average, I'm roughing that around the edges there, but it it was significant. So you're talking about a you know, your average 130 went or average 125 went to uh, you know, one 145 or whatever, 130 going to a 160. So yeah, it's that's 20 inches is a big deal in the white tail world.

Dr. Bronson Strickland 47:26

Uh I actually calculated that earlier today. It will it was over in in both treatment areas, it was over 25 inches. One of them was almost almost a 30-inch difference. Yeah, the memory was shortchanging it. Wow. You you had bigger sires. Yeah, we're big, we're better than we thought we were. Yeah. And then, yeah, bucks could not disperse. So there was not any swapping back and forth. It was in a in a in a high fence area, so that was controlled for. So why didn't it work?

Donnie Draeger 48:00

Why didn't it work? That's a great, you know, you hit on it a little bit. There is not enough strength and heritability of white-tailed deer to outweigh environmental factors. That's the best way I know how to say it in a layman's terms. Environmental factors, rainfall in our case, and and the timing of rain is important. And August rain doesn't do my deer much good from an antler standpoint, right? It's the spring rains. So the timing of rain is the number one driver of both reproduction and antler size in South Texas. Just no question, you know, timing and amount of rain. So that the genetics of what you may have, we increase the other aspect of is we were only affecting half of the equation. We were only calling the buck herd. So that takes your breeder equation for those scientists out there, and you have to put a half in there, unlike the cattle and livestock industry who can control that breeder equation both on both sides. So the you have male-female. We don't know how, no one knows how to judge a trophy female deer yet. I wish you guys would hurry up and figure that out. But if so, we're only affecting half of it. So you may have the best sire in the world with with a high breeding value, which we haven't gotten into yet. But if he mates with a really poor doe, then that negates itself. And so that's part of that that's my layman's way of describing it. I'll let you take a stab at it as well.

Dr. Bronson Strickland 49:48

Yeah, I don't know if I can do much better, but yeah, just the things listed here. Donnie, you've already covered the the rainfall. So variable environment. In your case, it's rainfall. It could be something else, some other environmental event in another part of North America. Because of that, we have the changing of the status. So from them switching from call to keep and keep to call, we're showing how that can change from year to year. And it's not genetic quality being demonstrated, it's environmental influences, is what you're seeing there. And then, of course, heritability. We'll get Randy to explain that to all of us a little bit better. Buck breeding value. And yeah, it's really, really inefficient when you can't control the the female. Yeah, let's you don't know

Breeding Value: The Scatter Plot That Changes Everything

Dr. Bronson Strickland 50:36

her genetics.

Donnie Draeger 50:36

Let's define breeding value since we have it there. I can do that real quick. I I always use the definition, it's the predicted estimate of worth of an individual's genotype based on the phenotypic values of its offspring and relatives. Genotype is a science way of saying what the DNA is coded for and how big that animal, or in this case, antlers, could be. The phenotype is the actual display of antlers that the animal has on its head any given year. And really, what we're looking for on breeding value is compared to each year's cohort. It could be a plus 20 breeding value. That means that that deer's offspring is 20 inches bigger on average than the average of that year's cohort. You know, because that that that intake that takes in the environmental effects, the year-to-year effects. So that's breeding value. And we found some really interesting things that I can do some color on in a minute if you want, of individual deer that had breeding values, both big and small, and how they how they lay out on kind of a scatter plot in your brain. That's really fascinating. No, this is the perfect time for that. Yeah, okay. I was hoping you'd do that. I I'm looking at this graph and I'm cheating on my computer. You know, you have so if if you can envision an XY chart, right? And then there's this scatter plot that just goes up to the right, that's gonna show and the bottom axis is your the gross minute crockett score of your sires. And the top and the y-axis is the breeding value of those that same animal, right? So and the middle of that y-axis is a zero. Below is negative all the way 40, and up is negative uh positive 40, right? So if you're a buck that's 125 and zero breeding value, you are perfectly average in every way. You're an average phenotype and you're an average offspring, right? It has zero. But if you're a buck that is 125 and a 40 plus 40 breeding value, then you're a buck that, even though he has a phenotype that only is 125, and actually what his antlers are, your offspring that on average, that buck's offspring are going to be 40 inches bigger than everybody else in the same cohort, his same age-class bucks, right? So what we found by doing that is we can we can show us uh the top tier of that graph, the top right, or the very high point, the high, anything above, let's say, 20 inches or better in breeding value, those are the deer that you want to be your breeders, right? And in everybody's mind, those deer are always the big antlered deer, right? The 180s, the 200s, the whatever your your magic number is out there. Well, in reality, on our scatter plot, what we showed is those deer run from the 125 mark. I think the lowest is about 120-ish, 123, all the way up to the 200-inch range. So you have this quadrant up there at the top of your XY scatter plot that are most definitely your breeder bucks. Those are the ones you'd want. The problem is they don't all look right phenotypically. They don't all have big handlers. Some of them are 125, some of them are 200s, right? To make it more complicated, there are also 200s on that chart that are way over to the right on the x-axis, right? But they're way low on the y-axis, and they have a negative 20 or negative 15 breeding value. So you have a 200-inch deer that his offspring will average 15 inches below the average for the cohort. That's insane, but that's what we found, and that is the that is why this system didn't work, because why that is is probably this environmental impacts and and then again that that pie chart I spoke of earlier, these unknown effects. But that's that's the that's the kind of the real take-home message here. When I said earlier, we haven't figured out how to judge or how to yeah, judge or or identify a trophy-producing dough. Well, the reality of it is we haven't figured out how to do that with bucks either. And that's one of my little comments that I always make when I give this speech is you may think you know because that one's got big antlers, but you don't know his breeding value. And and that's where the rubber meets the road. Yeah.

Dr. Bronson Strickland 55:34

No, that that's that's great. It is, man, that is so interesting. But but it's also enlightening from the perspective of is we're giving all these examples of why it doesn't work. And someone probably turns can turn around and say, well, obviously it has to work at some point, or we wouldn't have the deer breeding industry producing 300-inch yearlings. But but the difference is they have the pedigrees and they know the breeding value, they they know what type of offspring that individual buck and doe can produce on average.

Donnie Draeger 56:13

Yeah, both sides. Both sides. They don't have to take their breeder equation and you put a half in there where there should be a one, you know, and for those that and to that point, that same scatter plot, if you would just take this this range and the center median or the average deer in South Texas. So, you know, like we said, we have a bell curve of average deer in South Texas, right? That and the middle of that bell curve is 125, let's say. And if you take a range on five inches either side, so let's go to 120 to 130, all the deer in 120 to 130, and you just run that up that XY scatter plot. And so you're gonna calculate or you're gonna see every breeding value in that range, right? Well, that range runs as low as negative 23 breeding value all the way up to let me all the way up to a plus 30 breeding value. So that means that I mean you you don't want they don't get much higher than that. I mean, really, the plus 30 is about as high as we found, but it's right there on the cusp of the highest one. So how are you how do you go pick your bucks if your median average buck in the herd can be as low as 23 or as high as 30? That's a 50 inch, that's you know, almost as it is, it's a it's a 30, it's a 60, excuse me, I can't talk, a 60-inch difference in breeding value, all within the same buck category or score class, if you will, the 120 class, all right there. So that's what really complicates this, and that's why it's really hard for people to understand unless they listen to a podcast like this or happen to be at one of my talks. But you know, we're gonna the the the monograph is gonna help with that. As you know, I'm currently writing a layman's book to on this subject, and we'll have that out hopefully, you know, within a year or so. And but the uh it it is it never the more I talk about it, the more riled up I get because it's just such a an amazing thing to look at when you get when you get the data right in front of you.

Dr. Bronson Strickland 58:23

Yeah, I know, Donnie. The way you wrapped up there, the the this experiment was set up so well and it is so unique, and I completely agree. Seriously doubt it will ever be done again, not only because of the logistics of doing it, but I think also because of the results, in that when you look at the the the culling rate implemented, when you start looking because the the genetic samples were taken, and then you can look at the breeding value, you it starts to become very, very evident that why would you expect it to work? There's so many loose ends and there's so many things you can't control for. How could it work?

Donnie Draeger 59:08

Well, I I agree with you. I agree. But that let's, you know, uh

Why Some Ranches Still Appear to Succeed

Donnie Draeger 59:14

one of the slides I I I do in my talk is if it doesn't work, then why are some long-standing culling programs producing large antlered bugs? And and and we I Bronson, you and I both know multiple ranches, certainly here in South Texas, many ranches who have intensive culling programs. That and they are they work very hard at it and do a really good job at what they want to achieve, and they have tremendous deer herds, tremendous. No one could argue that. But the I know I know none of them with a control pasture, first off. So that is that's kind of my first opening salvo. If you don't have a control pasture, you don't get to have, I don't want to be that strong on it, but you don't have a fair assessment of your deer herd, right? The other thing that why these places still have big bucks is that most people who engage in an intensive culling program are all in on their deer herd because it's hard work. It is hard work to do that type of culling. And so they've probably already, and much earlier than when they started culling, they started a supplemental feed program. Certainly if you're here in Texas, you have maybe not all parts of the southeast, but where it's legal and people who have it have done that. Well, as we both know, supplemental feed over elevated high nutrition over generational time increases all metrics on whitetailed deer and any servant really. So you're gonna get bigger bodies, you're gonna get bigger antlers, you're gonna get all of those great metrics over time. In conjunction while you're doing supplemental, while you're doing culling, it people want to give their activity the credit for what's happening more than the passive, their active activity more than their passive activity. Passive activity is putting supplemental feed or out every day, all year long for 20 years, right? Or you know, shorter than that. But the active activity is culling, and people want to give credit to that, all that hard work and sweat. So and and the other aspect is you spoke of it earlier, Bronson, is the sculpted cohorts. The sculpted cohorts give the illusion that culling is working. Because when you drive around your ranch or you do your survey, the only thing you see are bigger deer. Yeah, you see bigger deer because you killed all the small ones, but that doesn't equate to genetic change, a shift in the genome or the DNA of the future generations are going to provide you with bigger antler deer on average. It's just that you keep knocking all the small ones out. So when you drive around, you have nothing but big ones. So that's another reason. And the in areas outside of western South Texas that that where my our ranches are, you also could have a density dependence response. So if you knock down the herd below canon capacity and everybody's got great groceries, then everybody's gonna, it's kind of the same as supplemental feeding. You have a higher nutritional plane for everybody, and they're gonna respond accordingly, which is gonna be positive, and you're gonna have bigger antlers, better body weights, all that, right? Well, if you're doing that while you're culling, you might equate that to improvements in culling. So you have all these things that that can do that that give the illusion that culling is working. And I don't think most people walk their way through that logic and and have a control pasture. I mean, if you do, good for you, and please raise your hand. I'd love to talk to you.

Closing & Preview of Part 3

Dr. Bronson Strickland 1:03:09

Well, Donnie, I think that's a good a good place to end. I think you covered it all very well there. And and I do appreciate you saying that because invariably someone that's involved with culling year after year after year will say just that. But I'm I'm seeing bigger deer. But again, that that is just a the the response of sculpting year in and year out these cohorts where the poor quality ones are removed, that is no genetic change. And you could you could always challenge them if it was a big genetic change. Well, stop calling and look at the next five years and and see if there's a difference. And if there was a big genetic change, then you would see a difference, but it it would just, you know, go back to to where they began. Well, Donnie, thank thank you. Number one, thank you for the time spending with with us here and talking to us about the study. Thank you for conducting the study, because that that is a really a landmark research project.

Donnie Draeger 1:04:15

I appreciate that, but I mean, fair is fair. And I was a that was a huge machine of really talented people from helicopter pilots to ground crew to scientists to my boss, who was forthcoming with his money and land and and time to to allow that to happen. And most importantly, his curiosity, what the same as mine, to go and get these questions answered. So don't thank me. Thank the team that was involved in that. And you're a part of that team, and I thank you for all the work you did on it as well.

Dr. Bronson Strickland 1:04:52

Absolutely. Lucky to be a part of it, man. Truly lucky to be part of it. Well, we will do part three. I will twist Randy DeYoung's arm to get him on here and we'll talk genetics, and I'll try to keep him from talking over everyone's head, but he can he can basically summarize some of these effects a lot better than me, me or Donnie could. But that that's what we'll do next time. But thank you, everyone. Thank you, Mariah. Thank you, Donnie. Good seeing you, and we'll see you next time.

Outro

Moriah Boggess 1:05:24

Thanks for listening to the Wildlife Investments podcast. For more information on these topics or to see some of the projects our team is working on, follow us on Instagram and Facebook at Wildlife Investments or visit wildlifeinvestments.com