How far we've come (buck age structure)

[BSK]

Finally finished analyzing some of the TWRA's harvest data, and below are two maps of the percent of harvested bucks 3 1/2+ years of age by county for the two five-year periods of 2005-09 and 2010-14. Although the 2010-14 data clearly shows some counties still have a ways to go, the improvements are obvious. The percentage of counties (with enough data for analysis) that would be in what I consider the "poor" category (<15% bucks 3 1/2+) has decreased from 61% during 2005-09 to 38% during 2010-14. The percent of counties in the "moderate," "good" and "great" category (>=15% bucks 3 1/2+) has increased from 39% during 2005-09 to 62% during 2010-14. In fact, the percent of counties in the "great" category (>=25% bucks 3 1/2+) has gone from 3% to 12%. Although of interest, a few counties have regressed a little.

 

[BSK]

To me, of most interest is how much better the northern Plateau Region is doing, as well as the Wilson-Rutherford-Cannon-DeKalb county region.

The Dickson-Hickman-Maury-Williamson county region is really hot, but then that area has been good for quite awhile.

 

[BSK]

I believe the above data is very interesting to the older/bigger buck hunting crowd, but as I was going through the raw data, I realized we are looking at the wrong thing. Considering the majority of hunters--who are the most likely to "harm" what most consider to be the critical buck age structure criterion (the yearling buck population)--I really think the data of most BIOLOGICAL value is the percent of the antlered buck harvest that is yearlings. I saw several counties that had low kill percentages of 3 1/2+ year-old bucks, but had amazingly low percentages of yearlings in the harvest as well. From a biological standpoint, those low percentages of yearlings in the buck harvest are far more important than the 3 1/2+ bucks.

If I get the chance, I'll recalculate the data for those two time periods looking only at the yearling buck harvest percentages. That should be a much better indicator of actual buck age structure in the standing population.

 

[duckriver]

Not trying to start a debate about online check in. But where does the TWRA get the info to age the deer if most are not officially aged? Thanks for the info

 

[280longshot]

Not trying to start a debate about online check in. But where does the TWRA get the info to age the deer if most are not officially aged? Thanks for the info

Kinda what I was just thinking...

 

[BSK]

Two sources: from specific check stations manned by TWRA biological staff on the opening weekends of MZ and gun season (unfortunately, only a small minority of check stations--they try to hit one per county); and from inspection of deer at local processors.

 

[Buzzard Breath]

Does "not enough data" mean no one was there to check? And, why did it go from 23 counties to 36 counties?

 

[usanglure]

TWRA had a survey of which our hunt club, Spring Creek Hunt Club, in Hardeman County participated in for them. I'm sure some of this data came from those surveys too.

 

[Shed Hunter]

TWRA had a survey of which our hunt club, Spring Creek Hunt Club, in Hardeman County participated in for them. I'm sure some of this data came from those surveys too.

That's even more reason to look at harvest data as irrelevent. Hunting clubs are generally going to have restrictions further than what TWRA sets as a guideline. They do not represent the actual average and below average property

 

[BigGameGuy]

TWRA had a survey of which our hunt club, Spring Creek Hunt Club, in Hardeman County participated in for them. I'm sure some of this data came from those surveys too.

That's even more reason to look at harvest data as irrelevent. Hunting clubs are generally going to have restrictions further than what TWRA sets as a guideline. They do not represent the actual average and below average property

That's why none of the Hunt club data is included in the maps above. Tennessee is one of the leading states in the accuracy of its deer data simply because we conduct a relatively random sample compared to other states.

 

[Planking]

My county is a stink fest...Figures.

 

[Buzzard Breath]

Unit b went from having 8 counties with "not enough data" to 12 counties with "not enough data". That tells me something is broke in this unit and needs fixed. Maybe the unit needs split into more than 1 unit because the counties that have data appear to be doing better.

 

[landman]

BSK
Thanks for doing this and posting

Stewart Counties increase doesn't surprise me

But Mintgomery County staying the same does

 

[BSK]

Does "not enough data" mean no one was there to check? And, why did it go from 23 counties to 36 counties?

I set a statistical requirement for the amount of data a county had to have to be of statistical value. Those counties with "Not Enough Data" didn't meet that requirement. Doesn't mean they didn't have any data, just not enough data.

 

[BSK]

Two sources: from specific check stations manned by TWRA biological staff on the opening weekends of MZ and gun season (unfortunately, only a small minority of check stations--they try to hit one per county); and from inspection of deer at local processors.

Quota hunts, too, I presume?

You'll have to ask BGG if the "County Biological Data" on their website contains WMA data as well as Open County data.

 

[BSK]

Unit b went from having 8 counties with "not enough data" to 12 counties with "not enough data". That tells me something is broke in this unit and needs fixed. Maybe the unit needs split into more than 1 unit because the counties that have data appear to be doing better.

The Not Enough Data category simply means there weren't enough bucks aged from those counties to produce valid numbers. Doesn't mean anything about the buck age structure.

 

[BSK]

My county is a stink fest...Figures.

And that's something not to be ignored. Although the percentage of counties with "poor" harvested buck age structure has declined dramatically, THEY STILL EXIST. These are the counties where I would like to see experimentation.

 

[turkeyhunter]

More big bucks killed in wayne co this season than i can ever remember. The self control used by hunters and killing of doe , has put our county in deer heaven in my opinion. I even hear young beginning hunters saying "i saw a spike today but we are waiting on a big buck". Weather was also a positive this season during key times of hunting.

 

[BSK]

More big bucks killed in wayne co this season than i can ever remember. The self control used by hunters and killing of doe , has put our county in deer heaven in my opinion. I even hear young beginning hunters saying "i saw a spike today but we are waiting on a big buck". Weather was also a positive this season during key times of hunting.

Wayne County, like the other Highland Rim counties, has another thing going for it: limited visibility. The short visual ranges of ridge-and-hollow hardwoods plays a much bigger role in growing older bucks than most hunters realize. I promise you it is MUCH easier to grow older bucks in the hilly big woods than it is in flat pasture or agricultural areas, where bucks are much more visible and harvestable.

In fact, all of the counties lining the east side of KY Lake (actually, extending two counties east of the lake) have such great buck age structures because of a number of common causes: decent deer density, large land-holdings and leasing of large chunks of land which leads to low or strictly controlled hunter densities, a high percentage of hunters passing young bucks, and limited visibility.

 

[Andy S.]

Good stuff Bryan, thanks for sharing.

 

[megalomaniac]

Really great stuff, actually!

What is most amazing is just how different age structures of bucks killed can be just across a county line.

In addition to yearling bucks percentages of harvest, it would also be interesting to see the differences between counties in mature bucks harvested (4.5 or older)... although since that's such a tiny percentage of the harvest, it would be hard to truly show a statistical difference between counties (be VERY difficult to get adequate sample sizes)

 

[BSK]

In addition to yearling bucks percentages of harvest, it would also be interesting to see the differences between counties in mature bucks harvested (4.5 or older)... although since that's such a tiny percentage of the harvest, it would be hard to truly show a statistical difference between counties (be VERY difficult to get adequate sample sizes)

I decided not to look at the mature buck harvest data because: 1) the numbers are so small that just one or two kills changes the percentages dramatically; and 2) the killing of mature bucks is far more about hunter skill and interest. Yes, the occasional mature buck falls to a casual hunter, but if you look at "club" data (hunters of all different levels/abilities hunting the same deer population) you will find that one or two very experienced "mature buck only" hunters usually end up killing the vast majority of mature bucks from a given property.

The yearling buck harvest percentages will be provide a much truer picture of hunter opportunity and choice.

 

[MUP]

Bryan, the thought just crossed my mind, wondering just how hunter density, per county, plays a role in these numbers. When you mentioned 3-1/2 yr old and yearling buck numbers being low in certain counties, just wondering if the hunter population may actually be significantly lower in those counties as well.

 

[deerchaser007]

Great info as always BSK! I know it takes you awhile to get all that info together and map it, and its always appreciated!

I noticed you spoke highly of my home county, cannon county. Since you put the meat on the table, I will throw in the beans and taters!LOL

HARVEST DATA
2002-total 769, buck/doe 426/343
2003-total 775, buck/doe 456/319
2004-total 817 buck/doe 478/339
2005-total 926 buck/doe 420/393
2006-total 993 buck/doe 440/447
2007 total 873 buck/doe 394/397
2008 total 773 buck/doe 314/383
2009 total 745 buck/doe 348/320
2010 total 840 buck/doe 416/344
2011 total 871 buck/doe 466/405
2012 total 938 buck/doe 523/415
2013 total 895 buck/doe 447/386
2014 total 994 buck/doe 520/419

BIOLOGIGAL DATA 2005-09 (90 total)BUCKS
AGE PERCENT Beam circum beam leth spread
1.5 56% 2.36 10.14 8.61
2.5 33% 3.23 15.86 13.4
3.5 6% 3.40 19.06 16.62
4.5 3% 4.04 18.97 16.33
5.5 1% 4.41 21.09 16.6
2005-09 (36 total) DOES
1.5 30%, 2.5 38%,3.5 14%, 4.5 5%, 5.5 11%

BIOLOGIGAL DATA 2010-14 (23 total) BUCKS
AGE PERCENT beam circum beam leth spread
1.5 44% 2.26 11.14 8.26
2.5 35% 2.63 14.65 13.14
3.5 22% 2.54 19.54 16.10
4.5 0 0 0 0
2010-14 (6 total) DOES
1.5 20%, 2.5 60%, 3.5 20%


What I find interesting in this data is even after 12 years of much of a sustained harvest, with the buck/doe harvest above/at/near 50%, cannon county had 0 bucks above 4.5 in the sample after 2009. Futhermore, beam circumference,length, and spread decreased in inches on the 2.5 and 3.5 year old buck classes. What I find the most interesting is my cam data shows the same, decreased inches after the year 2011 on the older age class bucks,3.5+. It just seems odd to me we are doing everything pretty well as far as harvest in cannon county, sustaining the herd at or below capacity, but antler inches are decreasing. I have my assumptions, but will keep them to myself due to it always causes a fuss on here, but that is the data and the data don't lie. SO, before I get bashed, this post is not about trophy bucks, this is standard quality deer management for the health of our herd for future generations. If by chance we are removing to many of our healthiest deer from the herd thru harvest(both buck and doe), this will have a negative affect in the next 10 years. These are questions that need to be asked, we don't have live weight data to use statewide to judge the health of our herd. Using the tools that we have should be indicators, and those numbers above don't lie. Straight up, healthier bucks will produce more inches, not decrease inches. The soil has not changed the past 5 years either. Cannon county may be the only county in the state with data similar, but it might not be either. Just IMO. I'm no expert!

 

[348Winchester]

BSK, what are your thoughts on the northern plateau?

 

[BSK]

Deerchaser007,

Something must be wrong, because your data-set for Cannon County for the period 2010-14 lists 23 bucks. Mine shows 67, with 3.1% mature (4 1/2+).

 

[BSK]

BSK, what are your thoughts on the northern plateau?

Definitely one of the areas where harvested buck age structure has improved fairly dramatically over the last 5 years.

 

[BSK]

What I find interesting in this data is even after 12 years of much of a sustained harvest, with the buck/doe harvest above/at/near 50%, cannon county had 0 bucks above 4.5 in the sample after 2009. Futhermore, beam circumference,length, and spread decreased in inches on the 2.5 and 3.5 year old buck classes. What I find the most interesting is my cam data shows the same, decreased inches after the year 2011 on the older age class bucks,3.5+. It just seems odd to me we are doing everything pretty well as far as harvest in cannon county, sustaining the herd at or below capacity, but antler inches are decreasing.

Honestly, I'm not sure the 23 bucks in your 2010-14 data is a large enough sample size to say much of anything about antler size per age-class. That's why I placed statistical controls on my analysis. I didn't want small data-sets causing erroneous comparisons.

 

[scn]

Thank you, Bryan, for the great analysis!

 

[deerchaser007]

Deerchaser007,

Something must be wrong, because your data-set for Cannon County for the period 2010-14 lists 23 bucks. Mine shows 67, with 3.1% mature (4 1/2+).

That came from twra site. Biological data per county from 9-15-10 til 1-31-15. The only bucks 4.5+ was in biological data from 9-15-05 til 1-31-10. I will go back and double check, but are you getting your info from somewere beside twra website? Is there another link to updated info that I am missing? Its very possible you may have collection data from this past season that they have not updated on their site yet. I know they collected data from local processor this past season, and that may be the info I do not have. I thought something was strange about that 23 number in a 5 year period, cause TWRA is usually here every other year or so, and that should warrant more than 23.Let me know, cause I hope your right and I'm wrong.

I agree that a sample of 90 from one 5 year rolling period, to a sample of 23 the next 5 year rolling period isn't in any way a great indicator. BUT, that's the great thing about RANDOM sampling that twra done. It was designed that way to get a unbiased data set.Its a tool, and was a valuable tool. I'm gonna miss that myself, and I believe future data collections will be somewhat biased due to they now tell hunters were they will be. BUT, twra does a awesome job,especially when it comes to data collection, so I'm sure after awhile it will become more RANDOM again even with online check.