Potential problems with field-judging age

[backyardtndeer]

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.

So do you think the possibility of lack of nutrition impacted the skeletal growth but not the body condition? If there was poor food available or lack of nutrition, wouldn't body condition suffer and be noticable through cams and sightings?

I would still lean towards the same opinion as Ski, that you and your clients had better habitat and just had more bucks move in.

 

[Ski]

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.

Only reason I even thought about it is because as I was reading your post I kept wondering to myself how you or your clients weren't identifying bucks from previous year(s). A buck doesn't change a lot in most cases other than size. I guess what I'm saying is that if they were the same bucks but didn't grow, I'd expect you to recognize them. Makes more sense it's just a bigger recruitment of 2.5yr olds that you've never seen before.

 

[BSK]

And before anyone mentions it, I want to throw out that the field-judge aging method is by no means perfect. It gets ages wrong. But first, it's the only method we have for aging live bucks and the only way to assess a standing crop of bucks. We can't run around asking all the bucks in a population to open their mouths so we can see their teeth. We can't pull a tooth from each buck and send it away for cementum annuli aging. So we go with field-judging age. How accurate is it? No way to know for sure, and would be heavily influenced by the skill/experience of the one judging the age, but getting to work with clubs over the long haul, I have the opportunity to check my age estimates against the tooth-wear ages of all bucks harvested on properties long-term. My accuracy (field-judge age matches tooth-wear) is right around 85% (whether that is the actual age or not is a question, as tooth-wear aging has it's problems as well). That's not perfect by any means, but it is "good enough" for managing an entire population.

 

[backyardtndeer]

Ha! Sorry buddy I missed that

lol. I miss stuff around here all the time, I was just kind of pointing out your not the only one thinking these new deer moved in and it is more likely that is how the drought may have indirectly impacted those age class numbers. Your analysis is typically spot on and I believe is again in this situation.

 

[BSK]

So do you think the possibility of lack of nutrition impacted the skeletal growth but not the body condition? If there was poor food available or lack of nutrition, wouldn't body condition suffer and be noticable through cams and sightings?

Yes, you would think so. I see no noticeable problems with body condition. Just possibly the musculature that is used for field-judging age.

I would still lean towards the same opinion as Ski, that you and your clients had better habitat and just had more bucks move in.

Why just 3 1/2s? And why not mature bucks? These properties are seeing a sudden decline in mature bucks in combination in an odd inflation in 3 1/2s. And some of these properties are in the thousands of acres, where they are not quite as affected by seasonal shifts.

 

[deerhunter10]

Makes sense. We did and still do have several 3.5 year olds seems to be a tick higher then normal. But that's probably from us misjudging them. Even our mature deer the few we have for sure seem smaller body wise in September and October then normal. And antler growth is average at best. The only difference Is we usually always have a mid 140s to low 150s deer on camera and we barely have one that would go 140 I think. Our top end isn't there. Also noticing lack of fawns from last year especially on our Hickman County piece. We saw zero rutting last year down there. Like I would say fawn numbers from previous years cut in half? And that's probably being generous. I would say if we didn't have the mass crop we have this year with the drought we have had I would hate to know what it would look like next year. As said above by mega the extent of the rut on some of these deer is something I've never really seen either. It has been a extreme and intense rut on our places.

 

[backyardtndeer]

And before anyone mentions it, I want to throw out that the field-judge aging method is by no means perfect. It gets ages wrong. But first, it's the only method we have for aging live bucks and the only way to assess a standing crop of bucks. We can't run around asking all the bucks in a population to open their mouths so we can see their teeth. We can't pull a tooth from each buck and send it away for cementum annuli aging. So we go with field-judging age. How accurate is it? No way to know for sure, and would be heavily influenced by the skill/experience of the one judging the age, but getting to work with clubs over the long haul, I have the opportunity to check my age estimates against the tooth-wear ages of all bucks harvested on properties long-term. My accuracy (field-judge age matches tooth-wear) is right around 85% (whether that is the actual age or not is a question, as tooth-wear aging has it's problems as well). That's not perfect by any means, but it is "good enough" for managing an entire population.

If you are at 85 percent as an expert in your field, that probably means your clients are less than that. Could account for some of the deviations, but I still think the deer moved in for better habitat and food when other surrounding areas were impacted.

 

[backyardtndeer]

Yes, you would think so. I see no noticeable problems with body condition. Just possibly the musculature that is used for field-judging age.

Why just 3 1/2s? And why not mature bucks? These properties are seeing a sudden decline in mature bucks in combination in an odd inflation in 3 1/2s. And some of these properties are in the thousands of acres, where they are not quite as affected by seasonal shifts.

The mature bucks probably hold tighter to their core area and don't transition as much. Especially around the rut, they are going to hit the areas they know, as where the younger bucks are still learning.

 

[Ski]

Why just 3 1/2s? And why not mature bucks? These properties are seeing a sudden decline in mature bucks in combination in an odd inflation in 3 1/2s. And some of these properties are in the thousands of acres, where they are not quite as affected by seasonal shifts.

That's a tougher question. Without it being reflected in harvest records or an EHD die off, it's hard to assume they died off or cease to exist. I understand why one would wonder if they're not just being misidentified as 3.5yr olds that were actually nutritionally deficient 4.5s. But I still think a 4.5yr old that didn't grow much would look nearly identical as it did at 3.5yrs, so I think you'd be seeing a dejavu effect. Since that doesn't seem to be the case, the older bucks have to be somewhere.

It's a stretch I know but could it be feasible that the older bucks simply were displaced by the influx of younger bucks? We know mature bucks prefer solitude, and once skeletally mature they require much less nutrition. They would be better suited to handle less than ideal conditions. Perhaps they simply moved off to less desirable areas away from the crowd. I assume camera locations for censusing haven't changed, so perhaps you're not seeing the mature buck numbers because they're no longer using those areas. I'd be curious if yourself or any of the larger property clients have went scouting to search if the mature bucks have simply moved away from the crowds.

Again, just guessing based on the info provided and what little i know about typical deer behavior. I don't really know what's going on. I'm not seeing it around here. But my curiosity would sure have me tromping around my property trying to find out what's happening. No sanctuary would be safe. I'd be over every inch looking for where the older bucks went. Hopefully you get it figured out. Weird for sure.

 

[BSK]

I went back and looked at the limited data I have from the last time we had a devastating drought - 2007. From the few data sets I have from 2008, I did not see this same surge of number of 3 1/2s and decline in number of 4 1/2+ year-old bucks. What does that mean? I have no idea.

But for now, I'm sticking to my theory that this year's rise in the 3 1/2s and decline in 4 1/2+ is due to mature bucks being mis-aged due to lack of body/muscle growth following last year's drought. Although other theories clearly exist, the misjudging age theory is the most logical (Ockhom's Razor).

 

[JCDEERMAN]

But for now, I'm sticking to my theory that this year's rise in the 3 1/2s and decline in 4 1/2+ is due to mature bucks being mis-aged due to lack of body/muscle growth following last year's drought. Although other theories clearly exist, the misjudging age theory is the most logical (Ockhom's Razor).

I'd say this is the most logical conclusion

 

[JCDEERMAN]

Per my initial post, just got pics of the jawbones of the buck killed. What do the experts say on jawbone? Again, the taxidermist said 5.5, but the buck's live weight was 167 lbs

 

[Ski]

Per my initial post, just got pics of the jawbones of the buck killed. What do the experts say on jawbone? Again, the taxidermist said 5.5, but the buck's live weight was 167 lbs

I know nothing about tooth wear aging. Makes zero sense to me. But those teeth look abused and well worn!

 

[backyardtndeer]

I went back and looked at the limited data I have from the last time we had a devastating drought - 2007. From the few data sets I have from 2008, I did not see this same surge of number of 3 1/2s and decline in number of 4 1/2+ year-old bucks. What does that mean? I have no idea.

But for now, I'm sticking to my theory that this year's rise in the 3 1/2s and decline in 4 1/2+ is due to mature bucks being mis-aged due to lack of body/muscle growth following last year's drought. Although other theories clearly exist, the misjudging age theory is the most logical (Ockhom's Razor).

It should be pretty easy to validate or discount your theory. You keep all your tail cam photos, just go back to last year and identify the 2.5's you know made it. Then look at this year's 3.5 year olds and record those you can identify. You should be able to identify if they added body size(increased skeletal size) from last year to this year. Then look at bucks identified as 3.5's last year and compare those known to their this year's 4.5's body sizes/shapes. If you really suspect your theory is right, you should be able to prove it with your saved camera files and data.

 

[megalomaniac]

Per my initial post, just got pics of the jawbones of the buck killed. What do the experts say on jawbone? Again, the taxidermist said 5.5, but the buck's live weight was 167 lbs

Unfortunately, that deer needed braces, so tooth wear is completely atypical and almost worthless. Excess wear on molars, less wear on premolars due to abnormal placement of premolars. Considering that, I'd go 3.5 to 4.5, despite the 3rd molar having wear typical of a 5.5 yo. But that's just a wild ass guess. But saying he is 5.5 based on that jawbone is also a wild ass guess as well.

 

[Ski]

It should be pretty easy to validate or discount your theory. You keep all your tail cam photos, just go back to last year and identify the 2.5's you know made it. Then look at this year's 3.5 year olds and record those you can identify. You should be able to identify if they added body size(increased skeletal size) from last year to this year. Then look at bucks identified as 3.5's last year and compare those known to their this year's 4.5's body sizes/shapes. If you really suspect your theory is right, you should be able to prove it with your saved camera files and data.

That's a pretty sound idea I think. Should be able to identify bucks, especially if they didn't grow much.

 

[BSK]

It should be pretty easy to validate or discount your theory. You keep all your tail cam photos, just go back to last year and identify the 2.5's you know made it. Then look at this year's 3.5 year olds and record those you can identify. You should be able to identify if they added body size(increased skeletal size) from last year to this year. Then look at bucks identified as 3.5's last year and compare those known to their this year's 4.5's body sizes/shapes. If you really suspect your theory is right, you should be able to prove it with your saved camera files and data.

You know, I haven't done that. Great suggestion.

 

[BSK]

Unfortunately, that deer needed braces, so tooth wear is completely atypical and almost worthless. Excess wear on molars, less wear on premolars due to abnormal placement of premolars. Considering that, I'd go 3.5 to 4.5, despite the 3rd molar having wear typical of a 5.5 yo. But that's just a wild ass guess. But saying he is 5.5 based on that jawbone is also a wild ass guess as well.

Agree completely. My opinion without having held the jaw in my hand so I can examine it closely, is 3 1/2.

 

[BigAl]

Question about the data you have for these properties, are any in or near the CWD zones? I admire the data you have, but am wondering if someone has the same historical data in CWD area.

 

[BSK]

Question about the data you have for these properties, are any in or near the CWD zones? I admire the data you have, but am wondering if someone has the same historical data in CWD area.

Only places just recently placed in the new CWD Management Zone, but not yet in the CWD Harvest Unit.