Jump to content

The science behind Buck to Doe Ratios  

5 members have voted

  1. 1. Do you believe Buck to Doe ratios can actually surpass 5d:1b after fawn recruitment and prior to the hunting season?

    • Yes, I've seen pre-hunt herds of 5:1 or greater.
      4
    • No, it's biologically impossible to exceed approximately 5:1.
      1
  2. 2. Do you count all antlerless deer in your ratios or only confirmed adults?

    • Only confirmed adults, fawns and unknown deer can't be accurately considered.
      3
    • I count all antlerless deer.
      2
  3. 3. After viewing the numbers below, have you changed your mind about the biologic possibility for greatly skewed D:B ratios?

    • Yes, I now believe that it's biologically impossible for a deer herd to have a D:B ratio greater than 5:1 (pre-hunt)
      1
    • No, I still think herds can reach D:B ratios higher than 5:1 (pre-hunt).
      3
    • I changed my mind the other way. Now I think they can go higher, before I didn't.
      0
    • I did not change my mind. I always believed they couldn't go higher than 5:1.
      1


Recommended Posts

Posted

I know that some hunters believe they have D:B ratios of 10:1 or greater where they hunt. I used to believe it could be true too.

 

What if I told you that was biologically impossible?

 

What if I told you that the highest D:B ratios can only reach approximately 5:1?

 

Here are some studies and articles that prove this to be true.

http://www.qdma.com/articles/the-reality-of-doebuck-ratios

http://www.ckwri.tamuk.edu/fileadmin/user_upload/docs/Deer_Research/publications_and_Presentations/Deer_Associates_Meeting/2012-3-8_The_Fallacy_of_Managing_the_Doe-Buck_Ratio.pdf

http://www.scentbuster.com/Doe-Buck_Ratio.html

http://www.scentbuster.com/uploads/Doe_to_Buck_Ratios.pdf

 

According to biologists, it's actually difficult for a deer herd to skew greater than 3:1 does:bucks with approximately 5:1 being the max.

 

Don't believe them?

 

Do the math, even with extreme numbers, such as 100% buck mortality and 0% doe mortality, the numbers constantly balance when the fawn crop hits the ground and last years fawn crop becomes part of the D:B ratio. 

 

 

Here's a more realistic graph showing how it self-balances:

b d ratios.jpg

 

So in summary:

 

- Doe harvests are most useful for controlling deer density, not D:B ratios. Need to lower the deer density, shoot does.

 

- Stopping the harvest of bucks will have a much greater impact on evening out D:B ratios. 

 

- 1:1 D:B ratios are difficult to achieve and sustain. Just under 2:1 is an excellent and more realistic goal.

 

- Stop counting fawns and unknown deer when you're trying to estimate the D:B ratio: Adult deer only and count prior to hunting season!

 

- The most important factors to concern ourselves with for a healthy herd are: availability of quality habitat/nutrition, balanced buck age structure and fawn survival.

 

- Most hunters "perceive" badly skewed D:B ratios, only because of improper observation techniques.

 

 

I imagine most hunters will take exception to all of this, but when you look at the numbers, it proves true.

 

 

 

“I have always tempered my killing with respect for the game pursued. I see the animal not only as a target, but as a living creature with more freedom than I will ever have. I take that life if I can, with regret as well as joy, and with the sure knowledge that nature’s way of fang and claw and starvation are a far crueler fate than I bestow.” – Fred Bear

Posted

Your biology is correct, but some hunters don't look at other factors.  I'll give you an example since you've been to my home here in Flanders.  Today was the perfect example.  I tossed out some corn and sunflower seeds when I was filling my bird feeders and 17 baldies came running in.  A quick glass-over with my binoculars showed that several were buttons but I didn't bother to keep count.  Still, no mature (18 month +) bucks among them.  That is a very common sight in the suburbs like where I live and one could easily believe the buck to doe ratio was far greater than 1:5.  But during the breeding cycles, I suddenly see groups of bucks that typically range from 4 to as many as 7 bucks chasing what are now small groups of 5 to 10 baldies with at least a few of those baldies actually being button bucks.  These bucks don't like the dogs and humans that abound in the neighborhoods and prefer more quiet woodlots and nearby farms, yet they are a part of our local herd, even if we don't see them nearly as frequently as we see all our bald deer.  So it does get confusing at times and the bigger picture is not always clear.  

 

Yesterday or Friday I watched a young 3 point mount a YOY doe born spring of '13.  That was the only buck I've seen lately, but they are around making more deer :)     

Posted

When people say b to d ratio what there really saying is Buck to BALDY ratio...or antlerless deer...

I absolutely get what your saying and do believe over half of fawns are bucks...

 

While hunting I definitely have seen over 10 antlerless deer to 1 buck... I believe theres a super high mortality rate on these young bucks.

referral-0686239001424316551.png

PredaTorch.com         Hot Estrous Doe and Other Deer Scent, Night Predator Lights

Posted

Although I missed the first two months of bow season with an injury this is what I've noticed.

I saw a group of 4 young bucks the first week of Jan along with one or two older, solitary ones. I am having trouble seeing big, mature older doe this season shooting last years fawns which weigh aprox 100lbs or so. I did harvest a decent 8pt and two younger doe but not one big, fat doe and I usually get at least one of those every season.

 I have seen more bucks this season than I have in many years past.

Elite Pure...
Bow only, deer hunter

Posted

I can't help but find it amusing that only one person changed their mind after reading over the population models.

 

Unless you kill the large majority of button bucks, 100% of antlered bucks and 0% of does, you can't get the population past 5:1. It's impossible.

 

Prove to me that you can with an accurate population model that goes as far in to the future as you want. Until then, anyone that thinks it's getting over 5:1 is ignoring science and math.

 

From a Maine study:

 

You can apply different known mortality rates and try to skew the ratio. Take a value of annual adult buck mortality of 67% (Heavily hunted population), an adult doe mortality of 25% (low doe hunting pressure), a fawn mortality rate of 51% and after 5 years the sex ratio works out to 1.7 does to 1 buck.

 

Biologically it is hard to make the case for adult buck to doe ratios being more skewed than 2 does for every 1 buck. - 

 

 

Now why do people observe more does (sometimes a lot more does) than bucks in the field? A number of things are at play here:

 
1. Bucks and does use habitats and forage differently at different times of the year. Large bodied deer (bucks) can afford to forage on food that is less nutritious than does, in other words larger deer can eat more low quality food to maintain body condition while smaller bodied deer need better forage to maintain and increase body mass. So females are seen along field edges and openings where they may find better nutrition versus the woods or swamp buck.
 
2. It is more common to observe groups of deer (many times a social group of related deer–i.e., adult female with yearlings and fawns) versus a single deer (buck)–although buck bachelor groups form as well.
 
3. An observed group of antlerless deer will likely include fawn bucks, sometimes yearling bucks where antlers are not apparent.
 
4. Bucks are notorious for being dodgy. We have done deer drives in exclosures with known numbers of deer and never see all the deer. Research has been conducted on large exclosure where they have gone into the fenced area and harvested all the deer using all kinds of methods. Getting every last one proves extremely difficult, and in a classic experiment in the mid-west, after they thought they had killed all the deer, they eventually found one last deer-a mature buck.
 
5. During the hunting season, especially in areas where there is lots of hunting pressure, the sex and age dynamics of the herd is being changed before your eyes. The greatest cause of buck mortality is hunting and that mortality is often condensed into a 4 week period where the herd dynamics are rapidly changing. So those are a few points.
 

 

 

Fisher's principle covers this and how a species self-regulates based on frequency dependent selection.

 

Frequency-dependent selection, in this scenario, is the logic that the probability of an individual being able to breed is dependent on the frequency of the opposite sex in relation to its own sex. It was first described by Darwin in 1871.

 

 

W.D. Hamilton gave the following basic explanation in his 1967 paper on "Extraordinary sex ratios", given the condition that males and females cost equal amounts to produce:

 
Suppose male births are less common than female.
A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring.
Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them.
Therefore the genes for male-producing tendencies spread, and male births become more common.
As the 1:1 sex ratio is approached, the advantage associated with producing males dies away.
The same reasoning holds true if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio.

“I have always tempered my killing with respect for the game pursued. I see the animal not only as a target, but as a living creature with more freedom than I will ever have. I take that life if I can, with regret as well as joy, and with the sure knowledge that nature’s way of fang and claw and starvation are a far crueler fate than I bestow.” – Fred Bear

Posted

When people say b to d ratio what there really saying is Buck to BALDY ratio...or antlerless deer...

I absolutely get what your saying and do believe over half of fawns are bucks...

 

While hunting I definitely have seen over 10 antlerless deer to 1 buck... I believe theres a super high mortality rate on these young bucks.

 

Buck to "baldy" ratio means jack squat. That's not an accurate measure of M:F ratio and it's one of the main points I was trying to make with this thread. To measure it is pointless.

 

Furthermore, it's biologically impossible for the actual sex ratio of a herd to be 10:1.

 

Without a doubt, I believe you could see antlerless deer at that rate, but the M:F sex ratio of the herd can't be that skewed, it's simply not possible. You're either counting fawns into the equation as antlerless deer, and certainly not seeing all the adult bucks in the area.  

 

Even with the highest mortality rates possible on bucks, it can not skew that badly. 

“I have always tempered my killing with respect for the game pursued. I see the animal not only as a target, but as a living creature with more freedom than I will ever have. I take that life if I can, with regret as well as joy, and with the sure knowledge that nature’s way of fang and claw and starvation are a far crueler fate than I bestow.” – Fred Bear

Posted (edited)

Buck to "baldy" ratio means jack squat. That's not an accurate measure of M:F ratio and it's one of the main points I was trying to make with this thread. To measure it is pointless.

 

How many times have we been surrounded by baldies on the golf course and there was not a single female in the bunch?  When I shot my October doe I had 2 antlered bucks, 3 BBs, a doe fawn and one mature doe at the feeder.  At a quick glance that would have looked like a 1:2.5 buck to doe ratio when in fact it was the exact opposite, there were 2.5 bucks per doe.

Edited by Rusty
Posted

Exactly Rusty!

 

I can still be considered guilty of this myself, because if I go out and see 4 or 5 antlerless deer in the distance, I simply say I saw 4 or 5 does. In reality I probably saw one or two adult does and 3-4 fawns. Now if I see a buck the same day, someone might say I saw a ratio of 5:1, which simply isn't accurate. What I really saw was somewhere between 1:1 or 2:1. Even then it may not be an accurate assessment of the sex ratio.

 

The fawns could have been 2 female and 2 male, or 3 male and 1 female. They don't count until next year though.

 

I also don't claim to be out there seeing more bucks than anyone else. I'm simply saying that if you're careful in your observations, many of the "does" we see, are actually young bucks and that even then, our observations can be skewed towards does because they are harder to ID as different individuals (something I haven't mentioned previously) as well as typically being more visible than bucks.

 

August seems to be a great time to go out and try to get a better idea of your approximate B:D ratios. Bucks are easily identifiable by their antlers, fawns are considerably smaller and spotted, so as not to be mistaken for adult does. And the majority of deer will freely use open fields at dusk for easy counts.

“I have always tempered my killing with respect for the game pursued. I see the animal not only as a target, but as a living creature with more freedom than I will ever have. I take that life if I can, with regret as well as joy, and with the sure knowledge that nature’s way of fang and claw and starvation are a far crueler fate than I bestow.” – Fred Bear

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...