Can the WI DNR count deer?
03-01-2003, 08:46 PM
#1
Fork Horn
Thread Starter
Join Date: Feb 2003
Location: Sussex WI
Posts: 381
Can the WI DNR count deer?
From the WI Outdoor News. Sorry about the length
Officials question DNR deer estimate
By Dean Bortz
Editor
Madison — Conservation Congress chairman Steve Oestreicher is willing to accept the DNR’s revised 2002 deer population estimate of 1.3 million, but he also hopes legislators will allow the congress to spend $75,000 on an outside audit of the DNR’s sex-age-kill (SAK) deer population formula.
Oestreicher is less willing to accept the DNR’s recommendation for 49 Zone T units in 2003.
Last week, just days after the DNR announced its official population estimate of 1.3 million deer heading into September of 2002, Oestreicher said he wanted university scientists from Missouri, Colorado and Washington to conduct an audit on the DNR SAK formula. It’s estimated that will cost $75,000, and Oestreicher said he has already approached Rep. Russ Decker (D-Wausau) and Rep. Scott Gunderson (R-Wind Lake) for the funding.
“Right now I’m looking for money for this audit,” Oestreicher said. “There are people around the U.S. who have been studying SAK and could come in here to conduct an audit.”
Oestreicher said he isn’t asking the DNR to abandon the SAK formula in reaching deer population estimates, but he’s interested in having the state learn whether there is a way to “tighten up” those estimates.
He pointed to the discrepancy between last summer’s “herd projection” and the current “population estimate.” Last summer, DNR biologists projected that the state had 1.6 million deer heading into the various fall deer seasons. Those projections are made every spring, then are verified with the subsequent harvest registration. Based on the 2002 bow, gun, muzzleloader, tribal and CWD registrations, that original projection of 1.6 million was “ground-checked” now at about 1.3 million heading into the fall of 2002.
“I’d like to get this audit completed as quickly as possible,” Oestreicher said. “Somewhere in the neighborhood of half a million deer have been lost by the SAK between last spring and now.”
One-half million? That might be a little high, according to DNR wildlife officials.
DNR population ecologist Robert Rolley of Madison took a few minutes to review the process the DNR uses to reach various projections and estimates. Rolley explained that the DNR has to make projections each spring for fall deer populations. Those spring projections are then verified through hunter registration of deer. The same process is being used right now to prepare for the 2003 deer seasons. Biologists will make projections in April and May (they want to see how the winter finishes up) and will use those projections to finalize antlerless quotas.
“The 1.6 million we thought we had last fall was a projection we had (based on) last winter’s post-hunt estimate,” Rolley said. “Every year we get a new harvest and then use that as the basis to estimate the population that produced that harvest. From the 2002 harvest, we’ll calculate the actual estimate of the pre-hunt population. From year to year, the population estimate could be different than the projection heading in. A population ‘projection’ is used to plan the harvest, then that projection is ground-proofed by the harvest and deer registration.
“Based on that process, we’re now saying we went into fall with about 1.3 million and came out with about 915,000 deer,” he said. “We’ll make forecasts later in the winter about what we might expect in the fall of 2003. By mid-March we finalize quota plans.”
So, is the difference between the 2002 projection of 1.6 million deer and the current estimate of 1.3 million (pre-hunt, 2002) a big deal?
“Some people might want to make it a big deal,” Rolley said. “There definitely were lots of things happening with this past season that caused us to have a little less confidence in estimates than a normal season.”
Some conservation groups that follow the annual herd population estimates say the numerous Zone T seasons and resulting high antlerless kills have made the SAK process less accurate, because it relies heavily on the buck kill.
“That’s not a good generalization,” Rolley responds. “Some of the areas where we had the most agreements between SAK and other modeling was in the eastern farmland region where we’ve had Zone Ts for several years now.”
Rolley said DNR biologists and wildlife managers had a number of questions on how to interpret the harvest across the whole Northern Forest Region.
“We saw a fairly substantial drop in buck kill in 2002 over what we’d seen in 2001, both in archery and gun seasons. We tried to interpret how much of that was due to reduced deer numbers, or for other reasons, most of which surrounded the CWD issue.”
Right now, the DNR has the statewide over-winter deer population at 915,000. The statewide over-winter goal is around 710,000 (now that goals were lowered in CWD zones).
“We are looking at 45 to 50 Zone T units. That will be firmed up and presented to the Natural Resources Board on Feb. 26. There will be no earn-a-buck in 2003 Zone T units, outside the CWD zones, but it could kick in in 2004,” Rolley said.
Conditions this winter are shaping up for another spring of good fawn production.
“All indications are we should have good fawn production. We could easily be back to 1.3 million by fall, but that’s not a prediction,” Rolley said.
In the meantime, Oestreicher will begin contacting three outside researchers on the possibility of conducting an SAK audit.
“The congress is still working with the DNR, but if there is a way to improve our SAK formula, or the process we use in reaching deer population estimates, why not do it?” he said. “The DNR is being aggressive with antlerless quotas despite the fact that the SAK came in lower than anticipated. I know they’re being aggressive in the event there are more deer out there than the SAK is showing.”
Officials question DNR deer estimate
By Dean Bortz
Editor
Madison — Conservation Congress chairman Steve Oestreicher is willing to accept the DNR’s revised 2002 deer population estimate of 1.3 million, but he also hopes legislators will allow the congress to spend $75,000 on an outside audit of the DNR’s sex-age-kill (SAK) deer population formula.
Oestreicher is less willing to accept the DNR’s recommendation for 49 Zone T units in 2003.
Last week, just days after the DNR announced its official population estimate of 1.3 million deer heading into September of 2002, Oestreicher said he wanted university scientists from Missouri, Colorado and Washington to conduct an audit on the DNR SAK formula. It’s estimated that will cost $75,000, and Oestreicher said he has already approached Rep. Russ Decker (D-Wausau) and Rep. Scott Gunderson (R-Wind Lake) for the funding.
“Right now I’m looking for money for this audit,” Oestreicher said. “There are people around the U.S. who have been studying SAK and could come in here to conduct an audit.”
Oestreicher said he isn’t asking the DNR to abandon the SAK formula in reaching deer population estimates, but he’s interested in having the state learn whether there is a way to “tighten up” those estimates.
He pointed to the discrepancy between last summer’s “herd projection” and the current “population estimate.” Last summer, DNR biologists projected that the state had 1.6 million deer heading into the various fall deer seasons. Those projections are made every spring, then are verified with the subsequent harvest registration. Based on the 2002 bow, gun, muzzleloader, tribal and CWD registrations, that original projection of 1.6 million was “ground-checked” now at about 1.3 million heading into the fall of 2002.
“I’d like to get this audit completed as quickly as possible,” Oestreicher said. “Somewhere in the neighborhood of half a million deer have been lost by the SAK between last spring and now.”
One-half million? That might be a little high, according to DNR wildlife officials.
DNR population ecologist Robert Rolley of Madison took a few minutes to review the process the DNR uses to reach various projections and estimates. Rolley explained that the DNR has to make projections each spring for fall deer populations. Those spring projections are then verified through hunter registration of deer. The same process is being used right now to prepare for the 2003 deer seasons. Biologists will make projections in April and May (they want to see how the winter finishes up) and will use those projections to finalize antlerless quotas.
“The 1.6 million we thought we had last fall was a projection we had (based on) last winter’s post-hunt estimate,” Rolley said. “Every year we get a new harvest and then use that as the basis to estimate the population that produced that harvest. From the 2002 harvest, we’ll calculate the actual estimate of the pre-hunt population. From year to year, the population estimate could be different than the projection heading in. A population ‘projection’ is used to plan the harvest, then that projection is ground-proofed by the harvest and deer registration.
“Based on that process, we’re now saying we went into fall with about 1.3 million and came out with about 915,000 deer,” he said. “We’ll make forecasts later in the winter about what we might expect in the fall of 2003. By mid-March we finalize quota plans.”
So, is the difference between the 2002 projection of 1.6 million deer and the current estimate of 1.3 million (pre-hunt, 2002) a big deal?
“Some people might want to make it a big deal,” Rolley said. “There definitely were lots of things happening with this past season that caused us to have a little less confidence in estimates than a normal season.”
Some conservation groups that follow the annual herd population estimates say the numerous Zone T seasons and resulting high antlerless kills have made the SAK process less accurate, because it relies heavily on the buck kill.
“That’s not a good generalization,” Rolley responds. “Some of the areas where we had the most agreements between SAK and other modeling was in the eastern farmland region where we’ve had Zone Ts for several years now.”
Rolley said DNR biologists and wildlife managers had a number of questions on how to interpret the harvest across the whole Northern Forest Region.
“We saw a fairly substantial drop in buck kill in 2002 over what we’d seen in 2001, both in archery and gun seasons. We tried to interpret how much of that was due to reduced deer numbers, or for other reasons, most of which surrounded the CWD issue.”
Right now, the DNR has the statewide over-winter deer population at 915,000. The statewide over-winter goal is around 710,000 (now that goals were lowered in CWD zones).
“We are looking at 45 to 50 Zone T units. That will be firmed up and presented to the Natural Resources Board on Feb. 26. There will be no earn-a-buck in 2003 Zone T units, outside the CWD zones, but it could kick in in 2004,” Rolley said.
Conditions this winter are shaping up for another spring of good fawn production.
“All indications are we should have good fawn production. We could easily be back to 1.3 million by fall, but that’s not a prediction,” Rolley said.
In the meantime, Oestreicher will begin contacting three outside researchers on the possibility of conducting an SAK audit.
“The congress is still working with the DNR, but if there is a way to improve our SAK formula, or the process we use in reaching deer population estimates, why not do it?” he said. “The DNR is being aggressive with antlerless quotas despite the fact that the SAK came in lower than anticipated. I know they’re being aggressive in the event there are more deer out there than the SAK is showing.”
03-01-2003, 08:56 PM
#2
Fork Horn
Thread Starter
Join Date: Feb 2003
Location: Sussex WI
Posts: 381
RE: Can the WI DNR count deer?
I especially love this quote, from one of the professional biologists:
Yeah, what the heck! Being off by a factor of around 20% ain' t no big deal![:@]
So, is the difference between the 2002 projection of 1.6 million deer and the current estimate of 1.3 million (pre-hunt, 2002) a big deal?
“Some people might want to make it a big deal,” Rolley said. “There definitely were lots of things happening with this past season that caused us to have a little less confidence in estimates than a normal season.”
“Some people might want to make it a big deal,” Rolley said. “There definitely were lots of things happening with this past season that caused us to have a little less confidence in estimates than a normal season.”
03-03-2003, 08:56 AM
#4
Fork Horn
Thread Starter
Join Date: Feb 2003
Location: Sussex WI
Posts: 381
RE: Can the WI DNR count deer?
Don' t get me wrong: I' m not looking for perfection by any means. But SAK has had such glaring statistical problems with it an audit of the result is way overdue.
Basically, here' s how it now works. SAK uses the previous year' s buck kill as one of the main variables to calculate the deer population. It doesn' t take into account the effect of T-zones and other antlerless kills. No wonder it appears that the population estimates are off by as much as 20%! So here we are, having all sorts of t-zones supposedly because so many units are " overpopulated" .
This has little to do with deer biology and more to do with statistical sampling. This method is flawed, plain and simple.
We were better off in the old days counting deer turds.
Basically, here' s how it now works. SAK uses the previous year' s buck kill as one of the main variables to calculate the deer population. It doesn' t take into account the effect of T-zones and other antlerless kills. No wonder it appears that the population estimates are off by as much as 20%! So here we are, having all sorts of t-zones supposedly because so many units are " overpopulated" .
This has little to do with deer biology and more to do with statistical sampling. This method is flawed, plain and simple.
We were better off in the old days counting deer turds.
03-04-2003, 10:04 PM
#5
Join Date: Feb 2003
Location: waukesha wi USA
Posts: 45
RE: Can the WI DNR count deer?
The sak seemed to have worked quite well when we had Edsels AND killed 2 bucks-1 doe. Now, it' s the other way around (according to their numbers). BUT, we don' t really know because we have no true number of buck or doe kill. We offered to fund this counting, since they said they were short of money, but they refused.
03-05-2003, 03:01 PM
#7
Fork Horn
Thread Starter
Join Date: Feb 2003
Location: Sussex WI
Posts: 381
RE: Can the WI DNR count deer?
Brian,
Great perspective! I had not thought of it in those terms, but I believe you' re on to something.
As an adjunct to your point, I remember seeing in the Deer 2000 stats...cannot recall exactly where...all of the areas where overwinter goals were lowered at some point in the 1990' s. Suddenly, areas that had not been considered as problems were now considered to be " overpopulated" , simply because the goals had been lowered.
I still have a problem with the way that SAK works. Having a decent statistical background, having buck kill as the main variable used to try and calculate population is going to be subject to a large standard deviation. An error of 20%...or more...would not be surprising. I don' t know what does work better, but the idea of an outside audit of the results can' t hurt.
Great perspective! I had not thought of it in those terms, but I believe you' re on to something.
As an adjunct to your point, I remember seeing in the Deer 2000 stats...cannot recall exactly where...all of the areas where overwinter goals were lowered at some point in the 1990' s. Suddenly, areas that had not been considered as problems were now considered to be " overpopulated" , simply because the goals had been lowered.
I still have a problem with the way that SAK works. Having a decent statistical background, having buck kill as the main variable used to try and calculate population is going to be subject to a large standard deviation. An error of 20%...or more...would not be surprising. I don' t know what does work better, but the idea of an outside audit of the results can' t hurt.
03-06-2003, 07:43 AM
#9
Fork Horn
Thread Starter
Join Date: Feb 2003
Location: Sussex WI
Posts: 381
RE: Can the WI DNR count deer?
Brian, I agree. I think WDHC' s point concurs with that as well. SAK would be fine under the " old" structure we had 10+ years ago. That is, no t-zone, etc. That is not the situation now. And as you put it, adding forumlas to formulas is tricky business. This in large part explains the 20% disparity in deer count that appears to be the case this year. With that margin of error, SAK becomes worthless.
Again, I think the overwintering goals are part of the problem in many areas. And " hunter satisfaction" is one issue that the DNR cannot simply ignore when coming up with population goals. As they have stated many times, hunters are their primary " deer management tool" . It' s not smart to create animosity with your most important " tool" , especially given the fact that you might need them down the road for, let' s say, an " eradication zone" . On a previous thread, I raised the issue that the DNR is their own worst enemy when it comes to PR. Not that it is possible or even desireable to try and structure things so that everyone is happy. But when we see polls like the one that came out of the Deer 2000 survey that indicated only 18% of hunters had a high degree of confidence in the DNR, that indicates a problem.
Again, I think the overwintering goals are part of the problem in many areas. And " hunter satisfaction" is one issue that the DNR cannot simply ignore when coming up with population goals. As they have stated many times, hunters are their primary " deer management tool" . It' s not smart to create animosity with your most important " tool" , especially given the fact that you might need them down the road for, let' s say, an " eradication zone" . On a previous thread, I raised the issue that the DNR is their own worst enemy when it comes to PR. Not that it is possible or even desireable to try and structure things so that everyone is happy. But when we see polls like the one that came out of the Deer 2000 survey that indicated only 18% of hunters had a high degree of confidence in the DNR, that indicates a problem.