Herd structure

[wh1stler]

Quote:

...when a deer herd has a proper buck/doe ratio and has proper age structure...

I picked this off another tread because I wanted to start a fresh discussion.

I have seen phrases similar to this posted here, there and everywhere but I really don't know what it means. Well, I understand the proper buck/doe ratio (approx. 1:1) but don't understand what is the proper age structure for herd of deer.

For the sake of simplicity, let's imagine a hypothetical wild herd of deer (call it Whistler's Herd, or WH for short). Let's assume that consists of 50 bucks and 50 does before fawning in the spring (i.e. the youngest deer in this herd are nearly 1 year old). What is the ideal age breakdown of this herd?

How many:

1 year-old bucks?

2 year-old bucks?

3 year-old bucks?

4 year-old bucks?

5 year-old bucks?

6+ year-old bucks?

I'm interested in everyone's opinion on what these numbers should be. Thanks much.

Wh1stler

[sparcebag]

This herd whats its area? A does home area is about 1 sq mile where a bucks is about 5 sq miles.How many bucks are inter mingeling in this herd? and how many are traveling to other herds?

Where does the 1 to one ratio come from?

[BobT]

I was thinking along similar lines. Where do you get the 1:1 as being ideal? My thought would be that's too many bucks but I'm not a biologist.

I also wonder about what is considered the best buck:doe ratio and why. Secondly, I wonder also what is considered the best age structure and why.

Bob

[Bear55]

Good questions and I guess I'm not reall sure there is a perfect answer. I would guess a natural herd would be fairly close to 1:1 ratio but slightly favoring the does because less bucks may make it to an older age because of fighting or stress. I would also guess that the population will tilt a bit toward younger deer because some of the older deer would again be lost due to predators, disease, stress, old age or even the occiasional freak accident.

Just a wild guess:

Year/Buck/Doe

1/15/15

2/10/12

3/7/10

4/5/7

5/3/6

6+/2/5

That puts us at 42 bucks and 55 does but these are kind of random numbers I pulled out of my head and I have no scientific data or background to deem them worth anything.

[Bear55]

I was thinking along similar lines. Where do you get the 1:1 as being ideal? My thought would be that's too many bucks but I'm not a biologist.

I also wonder about what is considered the best buck:doe ratio and why. Secondly, I wonder also what is considered the best age structure and why.

Bob

I think the 1:1 ratio come about because the birth rate is close to 50/50 slightly favoring bucks I think.

[BobT]

I imagine between natural losses due to fall rut and hunter harvest that raio for a given birth year would change considerably after year two.

Bob

[kr8r.tom]

1:1 is the ideal in mother nature, you need the male and female to continue the species. if the herd wasn't manipulated(hunting)it would naturally be 50% male and 50% female. just as in humans it's roughly an even distrubution in male/female throughtout the world.

in age structure, we don't have 80% 10 year olds and the other 20% make up the rest, its evenly distributed with a few peaks and valleys every now and then. for example lets say the average life span of a deer is 9yrs, 33% would be fawn-3yrs, 33% 3-6yrs and 33% would be 6-9yrs old.

a true biologist would try to attain a structure that mother nature intended, not an easy task but they(dnr) decided to be the biologists on our behalf.

[Bear55]

I imagine between natural losses due to fall rut and hunter harvest that raio for a given birth year would change considerably after year two.

Bob

If you add hunters in things would change a lot but the original question was about a natural herd minus the hunters.

[wh1stler]

Originally Posted By: BobT

I imagine between natural losses due to fall rut and hunter harvest that raio for a given birth year would change considerably after year two.

Bob

If you add hunters in things would change a lot but the original question was about a natural herd minus the hunters.

Exactly -- sort of.

[wh1stler]

Originally Posted By: BobT

I was thinking along similar lines. Where do you get the 1:1 as being ideal?

I think the 1:1 ratio come about because the birth rate is close to 50/50 slightly favoring bucks I think.

Googling the phrase 'ideal buck to doe ratio' brings a ton of information on this. In general, this is often (but not always) seen as the ideal ratio for a well balanced herd. Many professional managers in places like Texas aim for this ratio because at this point maximum rut activity is said to occur.

[wh1stler]

in age structure, we don't have 80% 10 year olds and the other 20% make up the rest, its evenly distributed with a few peaks and valleys every now and then. for example lets say the average life span of a deer is 9yrs, 33% would be fawn-3yrs, 33% 3-6yrs and 33% would be 6-9yrs old.

[sticknstring]

I'd venture a guess as you'd want a pretty even distribution among age groups. If the factor of hunting wasn't part of the equation, there would be a pretty similar hierarchy as human population age demographics. As said, a few spikes here and there (baby boomers) but pretty much even age class throughout.

In your example, that would mean 8-9 bucks in each of the 6 age classes.

[wh1stler]

I would also guess that the population will tilt a bit toward younger deer because some of the older deer would again be lost due to predators, disease, stress, old age or even the occiasional freak accident.

Just a wild guess:

Year/Buck/Doe

1/15/15

2/10/12

3/7/10

4/5/7

5/3/6

6+/2/5

That puts us at 42 bucks and 55 does but these are kind of random numbers I pulled out of my head and I have no scientific data or background to deem them worth anything.

These seem pretty reasonable. Thanks.

Any other thoughts?

Wh1stler

[JeffB]

In an ideal situation there would be one to many 6yr old bucks in the vicinity of my stand. The rest of the question is over my head.

[wh1stler]

I'd venture a guess as you'd want a pretty even distribution among age groups. If the factor of hunting wasn't part of the equation, there would be a pretty similar hierarchy as human population age demographics. As said, a few spikes here and there (baby boomers) but pretty much even age class throughout.

In your example, that would mean 8-9 bucks in each of the 6 age classes.

That would be a great starting point but when we think about sustaining the herd across multiple years that breakdown wouldn't work. As mentioned previously, it seems to me, that maintaining that structure would mean that bucks could not die until age 6+, most likey due to ld age. That is, a four-year old buck couldn't get taken down by wolves, disease or accident otherwise it leaves a diminshed number in his cohort that can never be replaced. Right?

I'm just trying to understand so don't take it personally.

Wh1stler

[wh1stler]

In an ideal situation there would be one to many 6yr old bucks in the vicinity of my stand. The rest of the question is over my head.

This might be the best possible answer to the question.

[sticknstring]

Quote:

That would be a great starting point

Exactly. You can let mother nature and circumstance take over after that. After years without hunting in the equation it'll become a scaled up version of what we have now with more generous 1-3 age classed animals and a smaller amount of deer 4-6 years old.

If only this example wasn't hypothetical

[BobT]

I beg to differ that taking human hunters out of the equation 50-50 ratio would be holding rather steady.

During the rut, bucks fight each other for breeding rights. I the process of doing this, they may or may not fight to the death however, they do get weakened and/or injured by the process and that makes them more susceptible to disease, illness, predation, and starvation than their female counterparts. For this reason I believe the males will naturally thin out faster than the females.

Relating this to human propogation isn't a fair comparison. On the lesser occasions that we do engage in these primordial battles we are more likely able to find medical assistance for our wounds rather than being left to die on our own.

Bob

[Bear55]

BobT

I agree the ratio wouldn't be exactly 50/50 but it would stay reasonably close, maybe 40/60 or 45/55. Sure bucks fight and die of stress but fights to the death are rare. A tough winter after a hard rut would have the best chance to take out bucks but they are still very tough creatures who most often find a way to survive.

I wonder if anyone knows the ratio in Fort Ripley? Yes we can hunt there but they would have harvest numbers so they might be able to determine something close to a natural ratio.

I read another intesting article in Deer and Deer Hunting a few years back stating that the buck/doe ratio can never get worse than 1:3. In the article they state that as long as all does were bred during the the rut and even if every possible buck (all ages) was shot the next years male fawns would bring the number up around 1:3. Of course this buck age structure would be worse than ours now but its something to think about.

[kr8r.tom]

35% fawn-2yrs-45% 3-8yrs and 20% 8-9yrs old would be more like reality. a natural buck/doe ratio has to be 50/50 without any manipulation(hunting,wolves ect.)..... i'll throw that out there

[wh1stler]

I read another intesting article in Deer and Deer Hunting a few years back stating that the buck/doe ratio can never get worse than 1:3. In the article they state that as long as all does were bred during the the rut and even if every possible buck (all ages) was shot the next years male fawns would bring the number up around 1:3. Of course this buck age structure would be worse than ours now but its something to think about.

Interesting...this is mathematically correct of course. I've never thought about it that way.

Thanks for the tidbit.

Wh1stler

[wh1stler]

35% fawn-2yrs-45% 3-8yrs and 20% 8-9yrs old would be more like reality.

so in my hypothetical herd you are suggesting:

9 - one year old bucks

9 - two year old bucks

(35% of 50 is 17.5, round to 18 deer)

5 - three year old bucks

5 - four year old bucks

5 - five year old bucks

4 - six year old bucks

4 - seven year old bucks

(45% of 50 is 22.5, or round up to 23 deer)

5 - 8 year old bucks

5 - 9 year old bucks

(%20 of 50 is 10 deer)

Unfortunately, mathmatically speaking, your model cannot work. You cannot have more 8 year old bucks than 7 year old bucks on an ongoing basis.

Wh1stler

[kr8r.tom]

o.k so plus minus a couple percentage points.