Studies that show buck harvest does not limit herd recovery

[elks96]

for years I have wanted to compile a library of studies on wildlife related issues. But have failed to do so… I have looked at a ton of different studies, papers etc.

Right now I am trying to support the argument that regulated buck harvest is not a limiting factor on herds so long as there is an adequate buck to doe ratio.

Does anyone have some studies to support this idea?

I know it is well accepted that female harvest is the way to control populations, I also know that 12 bucks to 100 doe is considered a baseline for buck to doe ratios. I know that high pregnancy rates is the first step. Then successful birth is the next, followed by fawn survival…

Does anyone have any proof that pregnancy rates are a problem in our herds?

Thanks…

 

[DaveD]

This doesn't directly answer your question but it is a good read that provides some fringe study that allows you to draw some conclusions.

https://onlinelibrary.wiley.com/doi/10.2981/wlb.00012

 

[DaveD]

And when combined with this study, I would draw the conclusion that buck harvest actually helps the herd recover as long as a minimum ratio of at least 12 bucks to 100 does is maintained.

https://fwp.mt.gov/binaries/content/assets/fwp/commission/2021/oct-28/wildlife/deer-ahm/4e---2018_final_mule_deer_-buck_harvest_by_response_variable_052518.pdf

 

[HikeHunt61]

This article on whitetails claims one negative about low buck ratios on next year's fawns. With fewer bucks, the "rut" takes longer for the bucks to service all the does. This leads to a larger birthing window in the spring, which can have detrimental effects on fawn survival including a wider window for predators and some late born fawns that do not survive the next winter.

It does not point to a study however.

Buck-to-Doe Ratios: Do They Matter?

Balanced sex ratios ensure healthy deer herds.

bowhuntersunited.com

 

[DaveD]

This article on whitetails claims one negative about low buck ratios on next year's fawns. With fewer bucks, the "rut" takes longer for the bucks to service all the does. This leads to a larger birthing window in the spring, which can have detrimental effects on fawn survival including a wider window for predators and some late born fawns that do not survive the next winter.

It does not point to a study however.

Buck-to-Doe Ratios: Do They Matter?

Balanced sex ratios ensure healthy deer herds.

bowhuntersunited.com

The breeding habits of whitetails and mule deer are not comparable. A mule deer buck can tend an entire herd of does at once, similar to elk, while whitetail bucks only tend one doe at a time. That does make buck to doe ratio much more important for whitetails.

 

[HikeHunt61]

For giggles and grins- I took the data from DaveD's article and did a scatter plot and a polynomial trend line. Buck ratio on horizontal axis, fawns on vertical:

 

[DaveD]

For giggles and grins- I took the data from DaveD's article and did a scatter plot and a polynomial trend line. Buck ratio on horizontal axis, fawns on vertical:

View attachment 113719

Production is only one element to the recovery. The interesting part to me was that there was lower fawn survival in areas that were managed for trophies and had a carrying capacity limitation due to winter forage limitations. It does make sense after seeing the data. If a certain winter range can only hold X number of deer on average, the population grows/recovers faster with buck to doe ratios in the 12-20 per 100 than it does with a 20-30 per 100 ratio because more of the deer are capable of producing a fawn. This of course is dependent upon there being just enough bucks to service all the does.

I think it is also worth considering the dispersal of mule deer bucks. Most 1.5 to 2.5 year old bucks will disperse to new ranges. Most only go 10-20 miles but they have been documented to go as far as 250 miles. If a region has a low number of bucks, they are more likely to take up residence there, somewhat balancing ratios throughout the mule deer range.

 

[HikeHunt61]

There's just never enough data, right?

Ya, it's a massively complex world out there. I'm sure deer density, doe dispersion, age class, migration habits/timing, carrying capacity and 20 other factors effect population growth.

I've always thought that herds with low buck/doe ratios are doomed in one sense: there is less natural selection of the most fit genes being passed along. When bucks do not need to compete for does, every buck gets a little tail.

 

[elks96]

Thanks, it is all very interesting. I Also feel that really high buck to doe ratios or bull to cow ratios can have some very negative impacts. I am very interested to see what comes out of WY as WY tends to have higher ratios.

As for the idea that lower numbers hurt, I am not sure that will happen since no matter what 50% of the genetics are the doe that don't really compete at all. There may be some issues but I think it would be really hard to show that impact if it does exist.

 

[elkassassin]

When Deer Are Once again Managed For Numbers of Deer Rather Than The Phoniest Type Of Management/Buck to Doe Ratio's Let Me Know!

When We Start Managing Deer When There's Still some Decent Genetics Left Doing Some Of The Breeding Let Me Know!

I Can Hear It Now:

By GAWD!

We've Only Got a 100 Head Of Deer Left!

Ya!

But The Good News Is There's 12 Bucks Left!

JFP!

 

[ICMDEER]

As a guy who ran research centers for decades, I'd be a little cautious with blanket statements about research results. I've been doing a lot of reading on some of the CWD studies lately and can honestly say there is so much bias and misinformation in those studies I am embarrassed for the wildlife folks who actually believe that hooey.

elkassassin has a great point. Our deer herds in SE Wyoming are only about 1/3 of objective. But buck/doe ratios are fine. Habitat is great. Deer are scarce. It's complicated but not tough to figure out what can be done to help. But our managers simply can't take those steps; not sure why.

There are some studies about mule deer that show when you have fewer bucks and younger bucks who are less experienced breeders, you do get an extended mule deer breeding and fawning season. It not only makes more fawns susceptible to predation, the younger fawns are smaller at weaning and more likely to be winter stressed or not survive a tough winter. Those smaller, younger deer are also less likely to breed as well and as early as bigger fawns in better body condition the following year. Same stuff holds true for livestock. Again, not rocket science.

Research on livestock will tell you you a bull can breed 50+ cows. Most ranchers figure 20-25 cows per bull. Better to be safe and get a good breed up. Same way for wildlife. May not be a limiting factor but better percentages of older age class bucks cover more does that first cycle and that has long-term implications for all sorts of stuff.

We also have to remember that this is just one piece of the puzzle. There's nutrition, predation, disease, interspecific competition (too danged many elk) and lots of other factors that come into play.

Also remember that the predators in Western Wyoming likely had a banner year. Lots of carcasses to feed on. Good breed up, lots of babies. There's also data out there that will demonstrate mule deer are also the "first choice" of many predators. If there are more predators chasing fewer mule deer, that's not always a good thing either.

Lots of stuff and answers are known. But other factors can't be quantified.

 

[ICMDEER]

Kinda like the old story about the two bulls that got turned out into the big breeding pasture with the cow herd. They came to the top of the hill and looked below to see a huge herd of cows. The young bull says "Let's run down there and breed one of those cows!!"

The old bull looks at the young one and smiles and says "Let's walk down there and breed them all." If any of you remember being a teenager, you might understand this.

I mentioned some research in my previous post, I take all of that "with a grain of salt." Guess it just comes down to common sense and experience as much as anything. But after living through the COVID debacle, I can assure you I take a serious look at any research before I take it as fact.

 

[woodruffhunter]

There are some studies about mule deer that show when you have fewer bucks and younger bucks who are less experienced breeders, you do get an extended mule deer breeding and fawning season. It not only makes more fawns susceptible to predation, the younger fawns are smaller at weaning and more likely to be winter stressed or not survive a tough winter. Those smaller, younger deer are also less likely to breed as well and as early as bigger fawns in better body condition the following year. Same stuff holds true for livestock. Again, not rocket science.

That is a great point.

 

[elks96]

As a guy who ran research centers for decades, I'd be a little cautious with blanket statements about research results. I've been doing a lot of reading on some of the CWD studies lately and can honestly say there is so much bias and misinformation in those studies I am embarrassed for the wildlife folks who actually believe that hooey.

elkassassin has a great point. Our deer herds in SE Wyoming are only about 1/3 of objective. But buck/doe ratios are fine. Habitat is great. Deer are scarce. It's complicated but not tough to figure out what can be done to help. But our managers simply can't take those steps; not sure why.

There are some studies about mule deer that show when you have fewer bucks and younger bucks who are less experienced breeders, you do get an extended mule deer breeding and fawning season. It not only makes more fawns susceptible to predation, the younger fawns are smaller at weaning and more likely to be winter stressed or not survive a tough winter. Those smaller, younger deer are also less likely to breed as well and as early as bigger fawns in better body condition the following year. Same stuff holds true for livestock. Again, not rocket science.

Research on livestock will tell you you a bull can breed 50+ cows. Most ranchers figure 20-25 cows per bull. Better to be safe and get a good breed up. Same way for wildlife. May not be a limiting factor but better percentages of older age class bucks cover more does that first cycle and that has long-term implications for all sorts of stuff.

We also have to remember that this is just one piece of the puzzle. There's nutrition, predation, disease, interspecific competition (too danged many elk) and lots of other factors that come into play.

Also remember that the predators in Western Wyoming likely had a banner year. Lots of carcasses to feed on. Good breed up, lots of babies. There's also data out there that will demonstrate mule deer are also the "first choice" of many predators. If there are more predators chasing fewer mule deer, that's not always a good thing either.

Lots of stuff and answers are known. But other factors can't be quantified.

I get the idea that fewer and younger bucks are low in number, but with point restriction and most units being high teens and 20s that should not be an issue?

You say that the numbers are low on the SE but buck doe ratios are good. You em say that it is complicated, but that the mangers don’t want to simply fix it.

So what is the answer? What would or should the mangers be doing that they are not? Is it just eliminating all doe fawn tags? Decreasing the elk herds?

Is the pregnancy rates low? Are the fawns weights low? Is it predators? You state it is not habitat? But is it habitat fragmentation?

Not arguing, I am just curious what you see…

I know studies I have worked with I. colorado showed that habitat, body weight pregnancy rates etc. were all good but in Colorado predation of neonatal fawn was a huge issue for growth/recruitment. Specifically the predation by black bears. But that was in NW Colorado with major bear issues.

The funny part is the study ended after 20 years showing it was not habitat, then 3 years later the biologist for the area convinced everyone that there were too many deer for the habitat and in the last 3 years they have killed over 750 doe in the same area where a nearly 20 year study showed it was not habitat…

I get not trusting the science, but there still has to be some truths.

 

[elkassassin]

ICM Gets It!

 

[ICMDEER]

There are several things that could be done:

1. Make lion season year round and eliminate quotas. The lions are a huge issue in our area. Some states allow trapping of lions. I'm for that as well. Let's admit we like deer and do what's best for them. I'd even be an advocate for lions and black bears to be reclassified by the legislature to predators. That's really what they are.
2. In Wyoming, we used to get a bear license when we bought an elk license. To encourage people to shoot bears, which are also lethal predators of fawns. We also need to kill more bears. Like lions, bear numbers are way up over what they were when I started paying attention. Extend seasons and increase quotas. Does anyone remember the Charles Kay study where one bear ate something like 45 calves in 25 days? We could easily do some telemetry studies to verify/quantify this. But no one will.
3. As you said, eliminate all doe harvest on mule deer. We currently have a three month mule deer doe season (4 months with archery) where I live. That is absolutely nuts. No reason for that.
4. Kill more coyotes. An honest bounty system would be beneficial. I used to manage the coyote bounties in Platte County. Fund aerial gunning of coyotes. It all helps.
5. The loss of wheat lands in eastern Wyoming to the CRP was a blow to mule deer. East of I-25, a high percentage of the deer wintered on those wheat fields. We lost about 250,000 acres of wheat in the three counties in SE Wyoming. Most of that went to grass monocultures; crested wheatgrass or smooth brome. Neither is worth anything for mule deer. If the USDA would require a legume and a good mix in the seedings, it would have really helped. And planting trees or shrubs in the CRP. Maybe even some water development in the CRP, with cost share incentives for the trees, shrubs and water. Maybe even some wheat for food plots for the deer. With incentives.
6. Yes, kill more elk. I do credit G&F here. They are trying, but it is a tough row to hoe.
7. Keep whitetails in check. They are doing well with this also.
8. We lose a ton of fawns to swathers in first cutting hay. A friend of mine cut up 50 fawns one year with his swather. They make extensions on cutter bars to help get those fawns up and away. But the new disc mowers eat the fawns so fast, you don't hardly know you hit one. Put incentives in place to avoid losing all those fawns to mowers and swathers. Cutting later really helps. Older fawns are more likely to get up and escape.

Those are some of the things that come quickly to mind. They could be done. But it's not likely that most or any will be done. Lots of factors and all Game and Fish talks about here is CWD.

We have lost sight of the fact that mule deer are THE PREMIER ANIMAL for Wyoming. (Yes, I admit I am biased, but this is MonsterMuleys.) I'll never elevate something like a lion, bear, or coyote to the status of a mule deer. I doubt a very high percentage of the population has even seen a lion or bear. But everyone has seen and loves to see a mule deer. And the deer are a far more important economic driver than lions or bears. Certainly more $$ to Game and Fish and more $$ to local economies if mule deer herds are at high levels and prospering.

Does that help outline a few alternatives?

Good question and good discussion.

 

[ICMDEER]

Just another note on lions.......

A rancher friend of mine in the Laramie Range has a 20,000 acre ranch. He has owned it for 44 years. Never saw a lion until 20 years ago. Now sightings are a regular occurance. He has about 100 trail cameras on his place. They now get pictures of 3-4 lions running together on a regular basis, and they often don't appear to be a female and kittens. He says every time he checks cameras, he gets lots of lion pictures. He has had deer literally killed within 50 yards of his house by lions. And he usually can't do anything about it.

Those lion numbers are way up and along with all of the other factors, they are keeping mule deer numbers depressed.

By the way, lion harvest quotas are set for our areas for the next 4 years. They can't or won't be changed on an annual basis like ungulate big game. G&F policy.....

 

[ICMDEER]

Here's some data on lions from Dr. Charles Kay:

•Most estimates are 1 lion kills 50 deer per year
•Estimate 36,000 lions in Western U.S.
•Kill at least 1.2 million ungulates each year
•In 1960, hunters took 764,000 mule deer
•By 2000, hunters took only 287,000
•Fewer today
•Quote from Kay “coyotes and black bears kill more deer each year than lions.”
•If lions kill 1.2 million deer and coyotes/bears kill more, how many are lost?

 

[SS!]

The title of the thread says it all. A path followed for a study to prove one’s opinion is a path with no end. Closed minds will eventually find a study to prove their point or find an example to disembody such research that is contrary to their beliefs.

Some great posts @ICMDEER . Thanks for taking the time to share them.

 

[elkassassin]

Well ICM!

You've Got A Perty Good Start There!

When Anybody With Any Sense At All Finally Realizes There Are 50+ Issue's Something Might Change!

The Deer Herd Should Be Extinct Before That Happens!

HELL-F'N-RIGHT!

 

[elkassassin]

It Amazes Me How Many Great White Hunters Try & Blame It All On One Thing!

JFP!

 

[wytex]

Yep, mt lions are not scarce for sure.
Have some working the deer herd right now on the ranch.

Have to say though, watched a golden eagle take a fawn right out from it's doe this weekend. Those birds can do a number on fawns too.
Mule deer can't catch a break it seems.

For open country we have a tons of black bears, with no quota, and mt lions with a quota. What is that logic?

 

[Bookhead]

Here's some data on lions from Dr. Charles Kay:

•Most estimates are 1 lion kills 50 deer per year
•Estimate 36,000 lions in Western U.S.
•Kill at least 1.2 million ungulates each year
•In 1960, hunters took 764,000 mule deer
•By 2000, hunters took only 287,000
•Fewer today
•Quote from Kay “coyotes and black bears kill more deer each year than lions.”
•If lions kill 1.2 million deer and coyotes/bears kill more, how many are lost?

Game and fish just finished a collar study on lions here go get the info from them. We do have areas that are already unlimited quotas and year round on lions and usually the kills in those areas are lower then those with a quota do you know why? The houndsmen are smart enough to regulate themselves for the most part their not going to eradicate the lions so it won't matter if you make it year round or not. I've been lion hunting here for 16 years in most mtn ranges not on the west side of the state but most others I see more elk and other game killed by lions then I do deer obviously they do kill deern no one is denying that. The lion populations fluctuate with the deer populations if you don't believe me look at the black hills the quota hasn't been met for lions the last couple years and why do you think that is when it used to fill after the first 3 snows every year? Because there's less deer so there's less lions. And if you have never hunted lions that would explain why you don't think they should be considered a trophy animal. They are one of the hardest and most rewarding animals to hunt here. Might get an easy one now and then but the hardest hunts I have been on have all been lion hunts behind dogs. Much harder then shooting a mule deer that stands there and stares at you after it knows your there or runs to 200 yards and stops and waits for you to kill it. A lion can and will take you miles upon miles into the nastiest country you ever stepped foot in before they give up the ghost allot of times.

 

[mevertsen]

Just another note on lions.......

A rancher friend of mine in the Laramie Range has a 20,000 acre ranch. He has owned it for 44 years. Never saw a lion until 20 years ago. Now sightings are a regular occurance. He has about 100 trail cameras on his place. They now get pictures of 3-4 lions running together on a regular basis, and they often don't appear to be a female and kittens. He says every time he checks cameras, he gets lots of lion pictures. He has had deer literally killed within 50 yards of his house by lions. And he usually can't do anything about it.

Those lion numbers are way up and along with all of the other factors, they are keeping mule deer numbers depressed.

By the way, lion harvest quotas are set for our areas for the next 4 years. They can't or won't be changed on an annual basis like ungulate big game. G&F policy.....

Curious on some specifics,

I am not familiar with the area, but a quick look at the regs shows that there are several areas where the quota is unlimited.

Also, I am not sure where to see the harvest stats to verify if any of the quotas are being met.

I ask because we have a 2 tag limit, 247 total quota, year rou d season here in NV. People complain all the time about lions, but we ha ent filled the quota, ever..

If the quota is being filled in the areas you are talking about, and there is proof of the lions being, a problem, then I see the argument for change.

If the quotas aren't being met under the current parameters, or if the ranch os in one of the unlimited quota areas, then it seems to me the rancher should fill all the tags he can, or try to find a solution with local houndsmen.

 

[Bookhead]

Curious on some specifics,

I am not familiar with the area, but a quick look at the regs shows that there are several areas where the quota is unlimited.

Also, I am not sure where to see the harvest stats to verify if any of the quotas are being met.

I ask because we have a 2 tag limit, 247 total quota, year rou d season here in NV. People complain all the time about lions, but we ha ent filled the quota, ever..

If the quota is being filled in the areas you are talking about, and there is proof of the lions being, a problem, then I see the argument for change.

If the quotas aren't being met under the current parameters, or if the ranch os in one of the unlimited quota areas, then it seems to me the rancher should fill all the tags he can, or try to find a solution with local houndsmen.

There ya go pretty funny I hear all about ranchers having lion problems and very few actually give a guy permission especially the biggest places