Buck to Doe Ratio

[billrquimby]

Guys, let's hope that AGFD doesn't rely on "one helicopter flyover every other year" to determine numbers of our wildlife. Years ago I was invited to ride in a game department-hired chopper in the Catalinas above Tucson.

 

The purpose was to look for sites other than Pusch Ridge still holding sheep.

 

We started by driving up the Sabino Canyon road at first light. I was surprised at just how many deer we saw along the creek as we drove up the canyon. They seemed to be everywhere, even standing in the shallow pools. When we boarded the chopper at the end of the road I was convinced we were going to see a ton of game, especially deer, that morning.

 

Well, we didn't.

 

We lifted off the pad and started across the face of the mountain at what seemed to be 50 mph until we reached Pima Canyon, ducked inside, and started going slower, hovering in a few places where the WM knew sheep hung out. We then rounded the ridge and hit the canyons on the north side of the ridge before returning to Sabino.

 

We saw maybe two dozen sheep and ZERO DEER! The sheep were seen only in the places they aleady were known to use. (IMO, though, it was because they were the only places we really searched.)

 

I believe the reason we saw no deer was because they didn't move until after the chopper had passed over them. We went slow and scoured the hillsides only where the WM expected to see sheep.

 

Another time I was part of a ground crew aiding in a survey on Pusch Ridge. We on the ground saw as many sheep with our binoculars and spotting scopes as the chopper crew found from the air.

 

In my mind, helicopters are only as good as the WM who is directing the pilot.

 

Bill Quimby

[firstcoueswas80]

to me it changes.... during hunting season, it seems like its one buck to every 20 does!!! then, when im either archery hunting pigs or looking for coyotes or what ever in the off season, its 5 bucks to every doe!!!

[25-06]

to me it changes.... during hunting season, it seems like its one buck to every 20 does!!! then, when im either archery hunting pigs or looking for coyotes or what ever in the off season, its 5 bucks to every doe!!!

I agree

[firstcoueswas80]

terry, i wondered if that only happened to me! seems to happen to me on bull elk hunts as well. the OPPOSITE seems to happen on cow elk hunts! on all 3 cow tags ive had, i chould have killed 1 360" bull and at least one 340" on each of the other hunts! heck, on the last one i could have killed a spike from camp!

[deernut]

Another good topic! I wrote a magazine article on this topic last year for the Mule Deer Foundation magazine that is posted as a pdf on my website. http://www.deernut.com/Documents/where_the...are_mdf2005.pdf

This article addresses the question "why am I seeing 20 does for every buck?" I won't repeat that information here.

 

I can tell who has a copy of my book by the postings - my chapter 7 (Reproduction) talks about the effects of wide buck:doe ratios on reproduction and herd "health." Chapter 9 (Management) goes through all the SW states one by one and describes exactly what survey, harvest, and misc information each state collects and how -- specifically -- they use that information to make hunt recommendations. Amanda posted the hunt guidelines the AZGFD uses to adjust permits in each GMU each year. These guidelines are not all they use and they are just guidelines (there may be other circumstances that come in to play (such as hunter access to deer habitat, crowding, etc.).

 

Scout'm: let me know what GMU we are all talking about and I'll provide some detailed information from the "Hunt Arizona 2006" book that is available to everyone from their local AZGFD office. I assume we are discussing whitetails, but I had to ask - it will make a difference in the data I provide. The average of all GMUs in SE AZ is 26 whitetail bucks:100 does. This is almost a 1:5 Buck:Doe ratio (26/126) which is phenomenal considering this is wide-open public lands hunting in the West. You would be very hard pressed to find ratios that good anywhere in the West. Which brings up one comment made earlier - please do not look to South Texas trophy whitetail population characteristics as a benchmark or think we should manage AZ deer populations that way. I am a writer for TX Trophy Hunters Magazine and I did my Master Degree work on whitetails in South Texas so I have quite a bit of experience in that realm. If we managed AZ deer herds that way we would have about 50 deer tags in each GMU.

 

About a third of the white-tailed deer aged in the field by Wildlife Managers are 3 years old or older. On the average (which fluctuates wildly year to year) only about 40% are yearlings - I think that is amazing for public land hunting. If more people in AZ want to go deer hunting each year, the AZGFD could let them them with absolutely no biological detriment to the whitetail populaitons (there are some social issues that would crop up, like "Hey, where'd the December whitetail hunts go?").

 

You will not be able to find any reputable research that shows a buck:doe ratio of 1:10 is harmful or limiting to the health of the herd in a meaningful way. As 'elkhunter' said all the does still get pregnant (let me know when you need a job). Colorado has done more research in this area than anyone because in the recent past they hunted their mule deer herds pretty heavily. Dr. Gary White at CSU analyzed 20 years of mule deer survey data and found that increasing the sex ratio from 10 to 40 bucks per 100 does only results in 7.4 additional fawns per 100 does/ That is a dramatic difference in buck:doe ratios and would require huge changes (=restrictions) in how you managed the deer population. Although there was a relationship between buck:doe ratios and fawn production, the effects were relatively minor and did not account for the long-term decline in recruitment CO experienced. Interestingly, no lower threshold in buck:doe ratios was detected below which recruitment dropped off rapidly. This also fails to support the theory that fewer bucks per doe dampens recruitment to any meaningful degree. Annual fluctuations in fawn recruitment due to rainfall and habitat conditions would totally swamp other minor affects.

 

As for our survey methodology, AZGFD has refined how they collect deer survey data over the last 20 years and currently about half of the deer observed during the survey period are from a helicopter which is a very effective way to survey rugged and remote deer habitat. They survey every unit every year the same way so they can monitor trends (a sample of the unit, not the whole thing). If it is too windy or rainy for good observations, the flight is postponed to the next open survey day at the end of the schedule. The helicopter doesn't go home until all units are surveyed in decent weather. The other half of the deer observations come from the local wildlife manager getting out there and glassing for deer every morning he/she can during the December 15 - February 15 survey period (when bucks are with does more). The 26 bucks:100 does mentioned above for all GMUs in SE AZ is based on 2,458 deer seen in 1,175 groups. Also, remember the surveys occur right after the hunts (few WT are surveyed until Jan) so the ratios used in management are minimums at their lowest point of the year.

 

Hope that helps.

 

JIM

[CouesWhitetail]

Thanks Jim!

 

For those that don't know Jim, he is the Regional Game Specialist for AGFD out of the Tucson office. He is a certified DEERNUT and has recently published a great book covering all kinds of topics related to both mule deer and whitetails. Check out his website and order a copy of the book!

 

Amanda

[scoutm]

Jim -

 

Great information! We spend most of our time in units 32, 33, 36c and on occasion 34b. We were in Unit 33 on the day this particular question came to mind. I would be very interested in seeing info on all these units.

 

As for the survey process...has GF ever considered broadening unit survey areas by using experience volunteers? It would be interesting to see if the results changed if volunteers were used on the ground in assigned areas.

 

Again, thanks for the info.

 

Larry

[shortpants]

Hey Jim, thanks for jumping in on this topic. I just wanted to say that I'm on chapter 9 of your book right now and it has been a facinating read so far. I can't wait to finish it cause I'm gunna start it all over again when I do. There's so much info crammed ito that book that there's no way I'll ever remember it all in 1 reading.

Thanks for the book!

[gamespec]

Sorry for the delay, I thought I clicked on the spot that would notify me of replys.

 

Our WMs surveyed (actually saw) 334 WTs in 137 groups during the Dec 15 - Feb 15 survey period in Unit 33. The Bucks:100 Does was 26, which is up from the 5-year average of 22. Our management guidelines indicate a decrease in permits when the B:100D ratio is below 20 and an increase above 30. This unit seems to be right in guidelines. As for Fawns:100Does we had 31:100 and that indicates a decrease in permits (range to stay the same - 35-45). The hunt success was 40% in the Oct hunt, 37% in the Nov hunt and 56% in the Dec hunt. That is very high! We now manage for 15-20% hunt success in the Oct/Nov hunts (the Dec hunt success is usually twice the Oct/Nov so we don't include that when deciding permit adjustments).

 

We have not used volunteers in the past because it takes a certain amount of effort to coordinate surveys and maintain consistency among surveyors. I have some hunting partners that I would not want contributing DATA to the state's survey database. I think just manageing the quality control among an army of volunteers would be difficult. You might have people also with dubious intents thinking that if they turn in mostly doe sightings then AZGFD will lower permits and make his archery spot better. We also need to make sure the same deer are not counted twice. WMs make sure they don't survey the same areas more than once. This would be harder to coordinate with volunteers. More importantly, we have analyzed the survey data over the years and found that when you reach a certain point, the ratios don't change. Once you get a sample size that adequately estimates the whole populaiton, then more deer don't change the overall estimate. Each WM has a target sample size and we reach that in most units.

 

Jim

[Red Rabbit]

Jim,

 

If the guidelines based on buck:doe ratio indicates that the number of permits should remain the same, and the fawn:doe ratio indicates a decrease in permits, and if hunter success was higher than goals, I ask why are the number of permits in unit 33 being increased by 50 or 5.9% ? Did the WM call for the increase? Did the dept override the WM and recommend the increase? If so, is this in the guise of increased hunter opportunity over the biological guidelines, or can the population handle the increase in permits over what the guidelines call for?

 

Doug~RR

[SunDevil]

thanks Doug - I was wondering the same thing. Chris.

[SunDevil]

Doug - you forgot about the addition 75 youth tags! how did that slip by you?

 

Jim - any info you can provide on the rational between the indicators and the recommendations would be greatly appreciated. thanks. chris.

[Red Rabbit]

Doug - you forgot about the addition 75 youth tags! how did that slip by you?

 

A) I was thinking about the late 12AW tag I will draw and was distracted by the increase in tags up there.

the junior hunt was printed on a different page

C) frankly in all the excitement, I overlooked the obvious

D) CRS

E) I knew you had me covered.

 

Doug

 

PS Chris-your inbox is full.

[kwp]

Jim,

 

If the guidelines based on buck:doe ratio indicates that the number of permits should remain the same, and the fawn:doe ratio indicates a decrease in permits, and if hunter success was higher than goals, I ask why are the number of permits in unit 33 being increased by 50 or 5.9% ? Did the WM call for the increase? Did the dept override the WM and recommend the increase? If so, is this in the guise of increased hunter opportunity over the biological guidelines, or can the population handle the increase in permits over what the guidelines call for?

 

Doug~RR

 

 

I was wondering the same thing too. I guess great minds think alike You would also think that they would have to consider overcrowding for this unit. I think that there are quite a few things that contribute to the overcrowding of a few key locations in 33 including the close proximity to a major metro area as well as only a couple of forest roads providing limited access to a small percentage of the total area in the unit. Those first two hunts are crazy with the number of people out in the woods, no way they should be increasing tags. Definately a case of increasing hunter opportunity ($$$$$) with no regards to biological guidelines

[gamespec]

I just noticed this, but have to get to the So. AZ Wildlife Callers meeting now to give a talk and then have to get my taxes done tonight. I'll come back to this Friday.

 

JIM