BHC
Well-Known Member
Any supported studies out there?? Preferably by she class...
Natural Non- Hrvest mortality rates?
- Thread starter BHC
- Start date
Shed Hunter
Well-Known Member
I would assume that number is hard to determine if not impossible. Coyote will kill fawns before we ever even know they were born, many EHD cases go unknown..etc. There may be studies done on this, but I doubt any accuracy.
BSK
Well-Known Member
No detailed studies of this because it is so hard to determine. Heck, we're still struggling to figure out how many deer actually exist, let alone how many die of natural causes.
BHC
Well-Known Member
Any validity to the bowman study here?
http://www.seafwa.org/resource/dynamic/ ... -76-81.pdf
http://www.seafwa.org/resource/dynamic/ ... -76-81.pdf
BSK
Well-Known Member
BHC said:
I can find no fault with that study nor the other studies sited. However, they found shockingly lower natural mortality for yearling bucks compared to previous studies, which found very high natural mortality rates for yearling bucks. I tend to agree with this concept, as yearling bucks lack experience, do "dumber" things during their first rut, and travel much greater distances than older bucks due to Yearling Buck Dispersal (YBD).
BSK
Well-Known Member
However, when considering the above listed study, remember one important thing: what the study was designed to find. This study was specifically designed to decipher if QDM works (buck survival by age-class) on VERY LARGE properties practicing QDM. The average size of the study properties was over 12,000 acres. Now the question is, how applicable is this data to the average hunter hunting/managing a property from 50 to 300 acres? Or even for the rare hunter hunting/managing a couple thousand acres? One thing I found very interesting was the high hunting mortality OFF THE STUDY PROPERTIES of all age bucks mentioned (greater then 50% for the age-classes mentioned). Considering the average property was greater than 12,000 acres, that's pretty amazing, and one of the reasons I usually tell hunters that I believe a property has to be 10,000 acres before they control the travels of even 50% of the bucks they get on camera.
BHC
Well-Known Member
My issue with it, is that if natural mortality rates are so low of deer 2.5-5.5. It would seem easy to achieve very very good age structure. And super high numbers of mature bucks. For instance on our property 3300 acres we have totaled 105 bucks and 99 bucks in the last two surveys. This past one had 32% two yr olds, 8% three yr olds, and 4% four plus yr olds. We kill very few 2.5 yr olds on our property, I'd say maybe one on our best yr and 4 on our worst. So if we were to have 32+ bucks entering the three yr old age class every yr, and we only kill say 12 and the 4 of our 8 4+ yr olds..We'de then have twenty 32 bucks the next season four plus yrs old. And a new batch of roughly 30 three yr olds coming up.. So in two seasons we jumped to 60 3+ yr old bucks when we only had 99 bucks to begin with total.., to me it just doesn't add up...
BHC
Well-Known Member
Sorry it'd be 28 4+ yr olds not 32.. Ha it's early
BSK
Well-Known Member
And there's the problem BHC. The difference between reality and theory, or using large-scale statistics to try and calculate reality in a small area. In fact, that's one of my problems with they way the photo census process is promoted. It is promoted as being able to produce accurate deer density figures for the censused area. Well I hate to tell hunters/managers this, but unless they're censusing an area of 40,000 to 50,000 acres, those density numbers are virtually meaningless for anything other than a trend indicator over time. Because deer move around daily, seasonally, and annually, the numbers generated from any property less than 10 miles across are going to be significantly inflated above reality. And the longer the census is run, the greater the inflation, as some already censused deer move off the study area and new ones move on.
The same goes for calculating mortality rates, both hunting and natural. Unless you are working with MASSIVE areas, bucks will be killed beyond the boundaries of the managed property. Even in the sited study, where study properties averaged over 12,000 acres, more than half of the harvest of some buck age-classes occurred OFF the study properties. Now think about the average hunter/manager trying to calculate buck loss rates for a 1,000 acre property? ALL of the bucks using that property probably also use surrounding properties, where they can be harvested.
Instead of trying to work out the population, harvest, and survival figures for a particular property using study numbers, here's what I recommend: collect real numbers for your property. Collect them for at least 3 years. Are the trends changing or remaining the same? Every property is going to be different, so only the REAL numbers matter.
And by "REAL" numbers, I mean the number of unique bucks in each age-class that use the property during the hunting season. In addition, calculate the buck age structure from those numbers. The questions to answer from that data are: 1) Is the percent of the buck population in each age-class changing over time? Is the number of bucks in each age-class changing? THOSE numbers will tell you what your real-world survival rate is in THAT area under THOSE local conditions (which includes all forms of mortality).
When you have this data for a number of years, you may find that your local conditions are not at all sensitive to what bucks are harvested from the property. On the other hand, you might find out that your local situation is HIGHLY sensitive to what bucks are harvested from the property each year. But the only way to know is to collect REAL data for THAT location.
The same goes for calculating mortality rates, both hunting and natural. Unless you are working with MASSIVE areas, bucks will be killed beyond the boundaries of the managed property. Even in the sited study, where study properties averaged over 12,000 acres, more than half of the harvest of some buck age-classes occurred OFF the study properties. Now think about the average hunter/manager trying to calculate buck loss rates for a 1,000 acre property? ALL of the bucks using that property probably also use surrounding properties, where they can be harvested.
Instead of trying to work out the population, harvest, and survival figures for a particular property using study numbers, here's what I recommend: collect real numbers for your property. Collect them for at least 3 years. Are the trends changing or remaining the same? Every property is going to be different, so only the REAL numbers matter.
And by "REAL" numbers, I mean the number of unique bucks in each age-class that use the property during the hunting season. In addition, calculate the buck age structure from those numbers. The questions to answer from that data are: 1) Is the percent of the buck population in each age-class changing over time? Is the number of bucks in each age-class changing? THOSE numbers will tell you what your real-world survival rate is in THAT area under THOSE local conditions (which includes all forms of mortality).
When you have this data for a number of years, you may find that your local conditions are not at all sensitive to what bucks are harvested from the property. On the other hand, you might find out that your local situation is HIGHLY sensitive to what bucks are harvested from the property each year. But the only way to know is to collect REAL data for THAT location.
BSK
Well-Known Member
BHC said:
And there's your answer. If 32% of your bucks are 2 1/2 years old, but only 8% are 3 1/2 years old, that's approximately a 75% total mortality rate of 2 1/2 year-old bucks. And I promise you that's not due to natural mortality. Even with 3,300 acres, if you aren't killing many of your 2 1/2 year-olds, people on neighboring properties are. And that's just a reality you will need to live with and manage around.
We kill very few yearling bucks on my property. Yet the annual mortality of yearling bucks is still 50%. And there's nothing we can do about that, other than manage with that knowledge in mind.
BSK
Well-Known Member
BHC said:
I don't know how long your group has been managing for older bucks, but don't get discouraged. QDM success can take a long time to "maximize" results. Although I have much less property to work with (3/4 of a square mile), we started QDM in 1994, yet our trail-cam surveys (started in 1999) indicated our buck age structure didn't "max out" until 2004. That's 10 years to see maximum results.
With the size property you have to work with, and continued protection of bucks until 3 1/2, I have no doubt that eventually you will reach an equilibrium of around 12-15% mature (4 1/2+) bucks in the adult male population.
BHC
Well-Known Member
Yes, well I feel like we may have been there, but killed to many bucks the last two yrs.. We killed 13 three + bucks in 2012, and 11 in 2013. Plus there were a few unrecovered deer as well that are not counted.., we saw a 30% decrease in 3+ bucks, and a 43% decrease in 4+ bucks since last survey....
BSK
Well-Known Member
BHC,
Just remember that with a POST-hunt census, if you increase the kill of 3 1/2+ bucks during the season, you will see a decrease in the number of surviving 3 1/2+ year-old bucks after the season is over. This isn't necessarily the sign of over-harvest. It's just a numbers game: kill more and you will have less after the season, but that isn't the definition of over-harvest.
Because you are limiting the harvest to bucks 3 1/2 and older, what I would be concerned with is the percent of the huntable buck population that is 4 1/2+. And the huntable buck population would be those surviving bucks post-hunt plus the ones you killed (the bucks on the property during hunting season). If you are killing too many 3 1/2 year-olds, that will show up in a declining percentage of the huntable bucks that are 4 1/2+ the following year.
I would also watch closely at the trend in total huntable bucks. You don't want to see your buck population declining too much. If it is declining over time, the trend in antlerless population may give you some idea why. If the antlerless population is NOT declining in unison with the declining buck population, excessive hunting pressure is probably to blame for the declining buck population (hunting pressure driving bucks away from the property). If the antlerless population is declining, then the declining buck population is linked to the overall population decline. That may be warranted (pushing the population down below the carrying capacity of the land) or it may be a problem (less deer not desired) depending on food resources.
Just remember that with a POST-hunt census, if you increase the kill of 3 1/2+ bucks during the season, you will see a decrease in the number of surviving 3 1/2+ year-old bucks after the season is over. This isn't necessarily the sign of over-harvest. It's just a numbers game: kill more and you will have less after the season, but that isn't the definition of over-harvest.
Because you are limiting the harvest to bucks 3 1/2 and older, what I would be concerned with is the percent of the huntable buck population that is 4 1/2+. And the huntable buck population would be those surviving bucks post-hunt plus the ones you killed (the bucks on the property during hunting season). If you are killing too many 3 1/2 year-olds, that will show up in a declining percentage of the huntable bucks that are 4 1/2+ the following year.
I would also watch closely at the trend in total huntable bucks. You don't want to see your buck population declining too much. If it is declining over time, the trend in antlerless population may give you some idea why. If the antlerless population is NOT declining in unison with the declining buck population, excessive hunting pressure is probably to blame for the declining buck population (hunting pressure driving bucks away from the property). If the antlerless population is declining, then the declining buck population is linked to the overall population decline. That may be warranted (pushing the population down below the carrying capacity of the land) or it may be a problem (less deer not desired) depending on food resources.
BHC
Well-Known Member
Here is some comparisons ive done to look at preseason numbers vs. post season numbers. This hopefully gives us an idea of where we stand. Also will give us a good of whether we are seeing decreases or increases from yr to yr.
2011 Post Season Survey
Based on the unique bucks identified and their age structure, we have approx. 227 deer, 105.6 bucks and 122.21 does within the area of the report.
Deer density: 14 acres/deer
Buck to Doe ratio: 1 buck : 1.16 does
Fawn recruitment: 57%
Buck Age Sturucture: 1.5 yr old= 60% = 63
2.5 yr old = 22% = 23
3.5 yr old = 10% = 11
4.5+ yr old = 7% = 7
- 18 bucks 3+ yrs old
2013 Post Season Survey
99 bucks
116 does Total pop. 260 deer
45 fawns
Buck to doe ratio = 1:1.17
Acres/deer = 12.7 for every 1 ( that is 1 deer per 12.7 acres)
Deer/sq. mile = 50.5
Buck Age Structure:
1.5 yr old = 55% = 54
2.5 yr old = 32.6% = 32
3.5 yr old = 7.9% = 8
4.5+ yr old = 4.5 % = 4
-12 bucks 3+ yrs old
Number of Preseason Bucks 3+ yrs old:
*Based on Post season data + Harvest Data Inserted: *Preseason-Mineral Lick Numbers:
2011=23 2011 = 26
2012=No Post Season Survey
2012 = 21
2013= 23
2013 = 26
When looking at the 3+ yr old buck numbers we have to consider our number of cameras, and camera sights have increased greatly from 2011-2013. Which probably contributes to the increase in population shown. Unfortunately the trend didn't follow for 3+ yr old bucks....
2011 Post Season Survey
Based on the unique bucks identified and their age structure, we have approx. 227 deer, 105.6 bucks and 122.21 does within the area of the report.
Deer density: 14 acres/deer
Buck to Doe ratio: 1 buck : 1.16 does
Fawn recruitment: 57%
Buck Age Sturucture: 1.5 yr old= 60% = 63
2.5 yr old = 22% = 23
3.5 yr old = 10% = 11
4.5+ yr old = 7% = 7
- 18 bucks 3+ yrs old
2013 Post Season Survey
99 bucks
116 does Total pop. 260 deer
45 fawns
Buck to doe ratio = 1:1.17
Acres/deer = 12.7 for every 1 ( that is 1 deer per 12.7 acres)
Deer/sq. mile = 50.5
Buck Age Structure:
1.5 yr old = 55% = 54
2.5 yr old = 32.6% = 32
3.5 yr old = 7.9% = 8
4.5+ yr old = 4.5 % = 4
-12 bucks 3+ yrs old
Number of Preseason Bucks 3+ yrs old:
*Based on Post season data + Harvest Data Inserted: *Preseason-Mineral Lick Numbers:
2011=23 2011 = 26
2012=No Post Season Survey
2012 = 21
2013= 23
2013 = 26
When looking at the 3+ yr old buck numbers we have to consider our number of cameras, and camera sights have increased greatly from 2011-2013. Which probably contributes to the increase in population shown. Unfortunately the trend didn't follow for 3+ yr old bucks....
BSK
Well-Known Member
BHC,
In 2013, how many 3 1/2 year-old bucks were killed, and how many mature (4 1/2+) bucks were killed?
In 2013, how many 3 1/2 year-old bucks were killed, and how many mature (4 1/2+) bucks were killed?
AlabamaSwamper
Well-Known Member
One thing is for sure, you will lose a LOT more bucks to unknown causes than to your gun. Whatever happens to them will probably remain a mystery forever but they are gone, out of the herd, that's for sure.
BHC
Well-Known Member
In 2013 we killed 7 bucks 3+ yrs old and 4 bucks 4+ yrs old.
BSK
Well-Known Member
BHC,
So by adding back in the bucks you killed in 2013, you had at least 109 bucks on the property, with an age structure of:
1 1/2: 54 (50%)
2 1/2: 32 (29%)
3 1/2: 15 (14%)
4 1/2+: 8 (7%)
That's not bad at all. In fact, it is very close to what I consider a very good buck age structure. I shoot for 15% 3 1/2s and 10% mature (4 1/2+) bucks. I do believe your harvest of 3 1/2 year-old bucks is having a measureable effect, but that effect is not excessive.
So by adding back in the bucks you killed in 2013, you had at least 109 bucks on the property, with an age structure of:
1 1/2: 54 (50%)
2 1/2: 32 (29%)
3 1/2: 15 (14%)
4 1/2+: 8 (7%)
That's not bad at all. In fact, it is very close to what I consider a very good buck age structure. I shoot for 15% 3 1/2s and 10% mature (4 1/2+) bucks. I do believe your harvest of 3 1/2 year-old bucks is having a measureable effect, but that effect is not excessive.
BSK
Well-Known Member
AlabamaSwamper said:
One thing I do agree with the earlier sited study (and other published mortality studies) is that the vast majority of buck mortality is due to legal harvest by someone, whether that someone is on the managed property or not. Now whether a buck that "disappears" from a given property from one year to the next disappears because of being dead is another question. But the fact that well-managed properties consistently see a 40-50% decline in the number of 2 1/2 year-old bucks from number of yearling bucks they had the previous year is due primarily to hunter legal harvest somewhere.
