Potential problems with field-judging age

BSK

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This topic won't apply to everyone in TN, just those who hunt/manage in the areas hit hardest by the 2022 drought.

First, let me say I'm not conclusively sure this problem is an absolute fact. It is based on an interesting trend I've observed having looked at a lot of photo census data and compared notes with many landowners/managers who collect trail-camera data. And this trend is - when looking at a census of the bucks using a given property - an unusually high number of 3 1/2 year-old bucks and an unusually low number of mature bucks (4 1/2+) this year.

Many factors influence a local area's "age pyramid" - the percent of the total buck population in each age-class. But it goes without saying that there will almost always be fewer bucks in each older age-class, because of all forms of mortality. In essence, you should see less 2 1/2 year-old bucks than yearlings because some yearlings are going to die each year, so fewer bucks that are 2 1/2 will exist the following year. This continues with each age-class. A local area's age pyramid - especially looked at over a number of years - should show the largest cohort is yearlings, the second largest should be 2 1/2s, the third largest should be 3 1/2s, etc. on up through all the age-classes that exist in the area. Now how big of a difference there is from one age-class to the next oldest will depend on many factors, but I find that the biggest factor is hunter harvest pressure. In fact, hunter harvest pressure is usually so obvious in the data I don't need to be told where the age-based limit for a club or big landowner is. I can see it in the data. If a club/landowner is using a rule (and that rule has been in place for a number of years) that bucks must be 3 1/2 before they are killable by hunters, I will see only a small drop in the number of 2 1/2s from the number of yearlings. The only loss of yearlings to 2 1/2s is through natural mortality - yearling bucks dying of disease, injuries, car collisions, etc. The same will be true of the decline in bucks from 2 1/2 to 3 1/2 - only a fairly small percentage decline. But because bucks are "legal" for harvest at 3 1/2, I will see a big drop-off in bucks from 3 1/2 to 4 1/2, and every older age-class as well, as hunters pick off a significant portion of each of these "legal for harvest" age-classes each year.

The point of all this is that, looked at over a number of years, I don't see big swings in the buck age pyramid on individual properties from year to year. Once a local area's age pyramid has developed - based on local harvest pressure - it stays very close to the same from year to year, with only slight differences. Even when hunters/managers change their harvest rules in attempt to produce an older buck age structure, the changes occur slowly from year to year. When properties make major changes in harvest guidelines to produce more older or mature bucks, the changes from year to year are incremental - just a couple of percentage points better from one year to the next (but these add up over time). Now there will certainly be vast differences in the buck age pyramid from property to property because of different amounts of harvest pressure and different self-imposed buck restrictions, but when looking at years of data from a single property, the numbers don't change quickly from year to year.

OK, after that exhaustive explanation, back to the original problem. And let me state again, I'm only seeing this problem in areas hit hardest by the 2022 drought - those areas where the drought was so severe that the acorn crop was a total failure, agricultural crops failed, food plots failed, and even the native habitat dried up (and I saw locations where even the pokeweed and ragweed dried up and died). The problem is a very odd number of bucks field-judged as being 3 1/2 this year. And when I say an "odd number," I'm saying some of these properties have come up with almost as many - and in some cases MORE - 3 1/2 year-old bucks than 2 1/2 year-old bucks. The accuracy of this scenario is highly unlikely. Not impossible, but highly unlikely.

My concern is, did the severe drought last year, and post-rut bucks going into a difficult winter (no acorns, no food plots, no agriculture) prevent surviving 3 1/2 and older bucks from adding the body growth the following spring/summer to "look like" they are a year older? The only explanation I can come up with for how numerous properties suddenly have more 3 1/2s than they had 2 1/2s the previous year is that some of those 3 1/2s are not 3 1/2. They are 4 1/2s (or even older) that were severely underfed the previous winter. This is pure conjecture on my part, but the numbers don't lie. If this occurred on just one property, I could come up with all sorts of potential explanations for it. But on multiple properties, all in the same region that all share the commonality of the drought? Yet in areas not as heavily affected by the drought I am NOT seeing this unusual pattern?

Again, this is pure speculation on my part trying to explain a regional anomaly. But it is an educated guess based on a lot of data over many years. But I could be wrong too and it's just an odd, highly coincidental anomaly.
 
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JCDEERMAN

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Thanks for providing that info and very interesting for sure. We all know taxidermists aren't the best of aging jawbones, but the one doing a euro mount for this one killed on our place this year said he was a 5.5. I suspected 4.5+ based on trail cam pics, but the deer only weighed 167 LIVE weight (which would be a normal weight for a typical 3.5 here). This could be a classic example of your prognosis. Once I get the pics of the jawbone, I'll post here for the real experts to chime in.

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megalomaniac

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I suspect your assumption is correct (there are several 4.5yo's being classified as 3.5yos due to inability to fully recover weight from the drought and last years rut). In years past, I've experienced an almost 'missing' age class (proportionally FEWER bucks of that age class, say 1.5yo's, 2.5yo's, or 3.5yo's due to unusually high fawn loss from predation. I hate seeing that, as I know it means I'm headed for a lean upcoming year/ years. But I've not seen what you are describing. But my farms although dry last year, received rains timely enough to not negatively affect habitat nor food plots.

Now this year, my plots are a total failure after only getting 0.75in rain over the 10 weeks after planting. But got plenty of rain until late August so we have a bumper acorn crop.

What I have found to be strange this year is how much weight the 4.5yo's lost during 1st rut. They always lose some weight, and so far I've only captured three 4.5y/os post rut, but all 3 have lost significantly more weight from 1st rut this year than any year in the past. Like scary amount... they are looking like bucks that have gone through 2 ruts and are January type pictures.
 

backyardtndeer

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Who is doing the field judging of the bucks ages, is it possible/probable that they were wrong?

The only way you could have more older age bucks in a specific age class would be if some moved into the areas from other areas due to lack of food or other issues where they previously were. Obviously you cannot increase the number of existing bucks in an age class in the following year.
 

lafn96

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I think you're very likely correct. Question though, how big of a difference is there typically from year to year in fawn recruitment rates? If there is a sizable difference, I would think that would also contribute?
 

TN Larry

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Very interesting and makes sense………how does the antler size compare to normal, average age class in these areas? If body weight was affected by the poor health due to the drought, shouldn't antler size also suffer? Just curious if there's a correlation there as well.
 

BSK

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Who is doing the field judging of the bucks ages, is it possible/probable that they were wrong?

The only way you could have more older age bucks in a specific age class would be if some moved into the areas from other areas due to lack of food or other issues where they previously were. Obviously you cannot increase the number of existing bucks in an age class in the following year.
Some of this data comes from my analysis of camera pictures and some from landowners' analysis. But all are experienced field-judgers, with man years of analyzing/field-judging local deer populations.
 

BSK

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I suspect your assumption is correct (there are several 4.5yo's being classified as 3.5yos due to inability to fully recover weight from the drought and last years rut). In years past, I've experienced an almost 'missing' age class (proportionally FEWER bucks of that age class, say 1.5yo's, 2.5yo's, or 3.5yo's due to unusually high fawn loss from predation.
I have seen a scenario once where a property/region experienced a "missing cohort." It was in the coastal region of SC, and the area experienced a severe tropical depression that flooded the region right at peak fawning time. We speculate many newborn fawns drown. We watched as that missing cohort progressed through the population for years. One year, an abnormally low number of years. The next year, an abnomrally low number of 2 1/2s. The following year, an abnormally low number of 3 1/2, etc.

But for this problem in particular, I went back and looked at previous years' data and could not find an "odd cohort" moving up the age pyramid that would explain this anomaly.
 

BSK

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Very interesting and makes sense………how does the antler size compare to normal, average age class in these areas?
And that's the interesting thing TN Larry. Most of these landowners have been commenting on how last year's drought didn't negatively affect antler production. But did it not? If some of these 3 1/2 year-old bucks are actually 4 1/2 or older, then antler growth assessments are being made using older bucks than the cohort suggests. In essence, if you're looking at the antler production of 3 1/2s, are you really looking at just 3 1/2 year-old bucks? Maybe some of them are older, and their antler growth - even if it is below average for their actual age - is skewing the assessments of true 3 1/2 year-olds.
 
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DoubleRidge

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Extremely interesting and it makes sense.
Actually last Saturday after the last camera card pull I thought to myself...I've never seen so many "good" up and comers...This could explain why...and reading the comments about the age structure pyramid....if I took this last card pull and tried to develop a pyramid...my guess is it would be heavy on 2½ and 3½ year old bucks (based off body conformation)....also have noticed some very noticeable weight loss in the November rut period.....Very interesting conversation...and these type conversations are exactly why I joined TnDeer.
 

backyardtndeer

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Some of this data comes from my analysis of camera pictures and some from landowners' analysis. But all are experienced field-judgers, with man years of analyzing/field-judging local deer populations.
Double counting same deer? How many times do we see members right here have one deer they think may be two different deer.

Really would surprise me for drought to lead to deer being misjudged across many properties. If anything, the drought this year has been nearly as bad as last, and if it were the case that drought was the sole factor in gross misjudging, you would again be seeing a broad number of that age class deer being under estimated on their ages this year. For us this year, we have seen very healthy heavy deer despite the drought. The 5.5 year old that I killed was easily over 200 lbs, he was the heaviest deer I have ever killed. The deer my wife killed about two weeks later did not have near as much fat, but was also heavier than the average 3.5 year old.
 

Snake

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Your assessment makes total sense and very logical ! Just as I mentioned deer in agricultural areas versus deer who's main diet is acorns . Diet would IMO have quite a bit of factor in the field judging of whitetails. So those in drought areas should be effected in their weight .
 

TN Larry

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At that's the interesting thing TN Larry. Most of these landowners have been commenting on how last year's drought didn't negatively affect antler production. But did it not? If some of these 3 1/2 year-old bucks are actually 4 1/2 or older, then antler growth assessments are being made using older bucks than the cohort suggests. In essence, if you're looking at the antler production of 3 1/2s, are you really looking at just 3 1/2 year-old bucks? Maybe some of them are older, and their antler growth - even if it is below average for their actual age - is skewing the assessments of true 3 1/2 year-olds.
That's kind of what I was thinking. Instead of looking at average to above average 3.5 yos, you could be looking at below average 4.5 yos.

This theory goes along with the mass thread you started a few weeks ago with a client having what looks like a 3.5 yo with heavy mass. The suspicion with the mass is that deer is older. Please update that thread with the jaw bone if that deer is killed and you can post it.
 

BSK

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Double counting same deer? How many times do we see members right here have one deer they think may be two different deer.

Really would surprise me for drought to lead to deer being misjudged across many properties. If anything, the drought this year has been nearly as bad as last, and if it were the case that drought was the sole factor in gross misjudging, you would again be seeing a broad number of that age class deer being under estimated on their ages this year. For us this year, we have seen very healthy heavy deer despite the drought. The 5.5 year old that I killed was easily over 200 lbs, he was the heaviest deer I have ever killed. The deer my wife killed about two weeks later did not have near as much fat, but was also heavier than the average 3.5 year old.
Actually, it is this year's bucks that may be being misjudged because of last year's drought. They came through the winter in terrible shape and couldn't put on enough body weight/growth this last summer to look a year older. So if this year's drought has a similar impact, it would show up next year (after the deer have struggled through winter).

But I doubt this year's drought will have anywhere near the impact. We had FAR in excess rainfall up until mid-August. Then the spigots turned off. But the spring and midsummer rains were enough many in the area are seeing the biggest acorns crop in years, and summer crops and natural habitat were not seriously impacted. Corn and soybean yields in my area were pretty good (unlike the previous year).

Double-counting bucks is always possible, but in most of these instances, either myself or the landowner is running a census that collects thousands, if not tens of thousands of images. Each unique buck may be photographed over 100 times. For me personally, I'm very hesitant to classify a buck as a unique buck until I have multiple pictures of him from multiple angles so I can point out the antler characteristics that make him unique. Even in the censuses I ran in the hardest hit drought areas, I'm coming up with an extraordinary number of 3 1/2 year-old bucks and an unusual lack of 4 1/2 year-old bucks on properties where I've been running censuses for years. However, outside of the worst drought areas, I'm not seeing this.
 

Ski

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I've got an alternative idea, although just a rational guess. Well managed properties are not only the best habitat in good years. They're also the best in bad years. In fact they really shine in bad years. As bad as things seemed to be on the managed lands, imagine how bad it was in unmanaged lands.

We know that the older a buck gets, the smaller his core gets. Yearlings and 2.5yr olds are still wishy washy. They'd be the first to vacate a barren land in search of greener pastures. Not coincidentally they'd congregate on the best properties. The result would be a lot of properties seeing very few bucks at all while a few seeing a big influx of middle age bucks.

The properties you work are all well managed and almost certainly offer more in the way of food than the bulk of surrounding properties. In very tough conditions they would be a shining beacon to deer that are willing to uproot and move. 1.5 and 2.5 year olds are just that type of deer.
 

Pilchard

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I don't have anything intelligent to add but would like your thoughts since it's somewhat on topic.

This is the buck I killed. Summer trail cam and teeth. I added the grip and grin to show its the same deer. Most said 4.5+ based on teeth when I posted it here.

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backyardtndeer

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I've got an alternative idea, although just a rational guess. Well managed properties are not only the best habitat in good years. They're also the best in bad years. In fact they really shine in bad years. As bad as things seemed to be on the managed lands, imagine how bad it was in unmanaged lands.

We know that the older a buck gets, the smaller his core gets. Yearlings and 2.5yr olds are still wishy washy. They'd be the first to vacate a barren land in search of greener pastures. Not coincidentally they'd congregate on the best properties. The result would be a lot of properties seeing very few bucks at all while a few seeing a big influx of middle age bucks.

The properties you work are all well managed and almost certainly offer more in the way of food than the bulk of surrounding properties. In very tough conditions they would be a shining beacon to deer that are willing to uproot and move. 1.5 and 2.5 year olds are just that type of deer.
Yep, I agree. Actually think I said the same thing, kind of anyway.😉
The only way you could have more older age bucks in a specific age class would be if some moved into the areas from other areas due to lack of food or other issues where they previously were.
 

BSK

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I've got an alternative idea, although just a rational guess. Well managed properties are not only the best habitat in good years. They're also the best in bad years. In fact they really shine in bad years. As bad as things seemed to be on the managed lands, imagine how bad it was in unmanaged lands.

We know that the older a buck gets, the smaller his core gets. Yearlings and 2.5yr olds are still wishy washy. They'd be the first to vacate a barren land in search of greener pastures. Not coincidentally they'd congregate on the best properties. The result would be a lot of properties seeing very few bucks at all while a few seeing a big influx of middle age bucks.

The properties you work are all well managed and almost certainly offer more in the way of food than the bulk of surrounding properties. In very tough conditions they would be a shining beacon to deer that are willing to uproot and move. 1.5 and 2.5 year olds are just that type of deer.
All possible Ski. Without question, most of this data is coming from fairly intensively managed properties, not only deer herd but habitat. I have no data from unmanaged properties, and that is always a real risk when trying to determine "what is going on."

Too often, like in this case, a situation arises that will require another couple of years of data to get a better feel of what was really going on.
 

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