By P.J. Reilly
Can you fix buck-doe ratios, and should you even if you could?
The second day of Illinois’ 2010 firearms season was foggy and warm. I couldn’t see more than 10 yards through the pea soup, so I heard the little doe coming well before I saw her. It wasn’t her footsteps that caught my attention; it was her incessant bleating.
She came straight to the base of my tree and bleated repeatedly. I faced the tree and pressed against it in hopes that if the doe looked up, she’d think I was part of the trunk.
My back was to the open woods, but I didn’t need to see the buck to know one had showed up and announced his presence with a loud, UUUUURRRPPPPP.
It was a deep, guttural sound — one of the loudest grunts I’ve ever heard. My heart started pounding as I slowly turned my head to see this vocal arrival.
Sure enough, a stout 8-pointer was standing some 30 yards away, staring intently at the little doe. I wish I could tell you I anchored that buck, but I can’t. In the dense cloud of humidity surrounding my perch, my muzzleloader could only muster a wimpy pffffftttt when I pulled the trigger.
That’s the way it goes sometimes, but the encounter was special, and one some biologists say I might not have experienced if the buck-to-doe ratio in White County had been heavily out of whack.
Odds are you’ve heard about buck-to-doe ratios and the benefits of having it as close to 1-to-1 as possible. The usual complaint is the local ratio is skewed in favor of does, which leads many to believe does should be targeted without exception.
But is that smart? Can you even do it? And what are the consequences?
The Case Against
A member of the advisory board for the Caesar Kleberg Wildlife Research Institute at Texas A&M University, Stuart Stedman tackled the subject in a presentation at a 2012 conference at the Faith Ranch in Texas, which he owns.
“Managing the doe-buck ratio is almost always the wrong approach to managing a deer herd,” Stedman said.
Kip Adams, a wildlife biologist and director of outreach and education for Quality Deer Management Association, agrees.
“Manage the herd for the number of deer the land can support, protect yearling bucks, and the ratio will take care of itself,” he said.
Why It Matters
Even though both agree a deer herd shouldn’t be managed to achieve an even buck-to-doe ratio, both men said there are benefits to having about the same number of bucks as does. Such benefits for hunters include having more vocal bucks, along with more sign (rubs and scrapes). Bucks living in areas with balanced ratios also tend to respond more to rattling and calls.
In the wild, fawns are pretty evenly split between males and females, Stedman said. So, based on births alone, a natural buck-to-doe ratio is 1-to-1.
Absent hunting, bucks have a slightly higher mortality rate than does. Account-ing for that mortality rate, Stedman estimates the natural buck-to-doe ratio of an unhunted herd is about 1 buck for every 1.2 does.
Throw hunting into the mix, he says, and things can go haywire.
“If the ratio in your area is skewed in favor of does, it’s because hunters are killing too many bucks,” he said.
True enough, says Adams, adding, “to keep the ratio of adult deer balanced, hunters should take at least as many does as bucks. And, actually, they should take even more does, because, outside hunting season, the natural mortality rate is higher on bucks.”
Location Matters, Too
The emphasis on targeting does is where Stedman and Adams differ, but only because they primarily work in different areas. Stedman advocates protecting does because, “They are your source of more bucks,” he said. “If you try to shoot your way out of a skewed ratio that favors does, you’re just limiting your buck production.”
Instead of shooting does to correct the ratio, Stedman advocates protecting bucks.
“Set a goal of shooting only mature bucks,” he said. “If you take only bucks that are 5½ or 6½ years old, then you’re going to reduce the pressure on the younger bucks and your overall buck numbers will increase.”
Many hunters Stedman encounters don’t think like that. “They say, ‘I’ve got too many does, so I need to kill a bunch of does,’ ” he said. “All you do in that case is reduce the size of your fawn factory.”
And in the whitetail-crazy country of South Texas, you need lots of bucks being born to increase the number of trophy-class males.
Most bucks, he explained, are going to have average racks, while a smaller percentage will be trophies (160 or more inches by his standards). To have a decent assortment of trophy bucks, you’ve got to have a lot of bucks.
Adams is aware of Stedman’s theories and was on hand at the conference. They “work very well for his part of the country in South Texas,” Adams said.
There, water is a precious commodity that often is in short supply. Whitetails don’t reproduce in the South Texas climate as heartily as they do in other parts of North America.
“In South Texas, the mortality rate on fawns is much higher than it is in most of the rest of the whitetail’s range in North America,” Adams said. “It might take three or four does to produce one fawn that survives to adulthood. So every doe there is precious.”
In other areas, though, fawns hit the ground in big numbers each spring, and many survive to adulthood. It’s in those areas where Adams said it’s not necessary to protect does. “You can shoot a lot of does and still have a healthy deer population,” he said.
Biologists and land managers need to determine how many deer the land can support, Adams said, and then work to get the herd to that level.
Assuming there are too many deer, getting the herd to the goal will require shooting does. At the same time, managers should also work to protect 1½-year-old bucks to make sure hunters are not overhunting the males.
Such a strategy will help even out the buck-to-doe ratio, although Stedman and Adams agree achieving an exact 1-to-1 ratio is virtually impossible in a wild herd.
Age Over Sex
Instead of focusing on the buck-to-doe ratio for managing a herd, Adams suggests managers look at the age structure.
“In a normal, healthy herd, you’re going to have animals in every age class,” he said. “You should have bucks and does that are 1 through 6 years old. If all you’ve got is a bunch of 1½-year-olds, that’s a poorly managed herd.”
When you protect the youngest bucks, there’s a ripple effect throughout the age structure. If you protect 1½-year-olds, you’ll have more 2½-year-olds. The more 2½-year-olds you have, the more 3½-year-olds you’ll have, and so forth.
There was a time when bucks were pounded with no regard to the age structure of the herd. Before it launched efforts to protect yearling bucks back in 2002, the Pennsylvania Game Commission estimated there were areas in the state where hunters killed 90 percent of the yearling males every year. That was a contributing factor to a statewide buck-to-doe ratio that agency officials said greatly favored does.
Two years ago, more yearling bucks than ever before were given a pass by hunters across the United States. QDMA reports that only 37 percent of antlered bucks shot during the 2012-13 season were 1½ years old. That’s down from 62 percent in 1988. That means 63 percent of bucks shot during the 2012-13 season were 2½ and older.
“The trend is clear,” Adams said. “More deer hunters are choosing the benefits that come from protecting yearling bucks and building numbers of older bucks in a deer population.
The decline in yearling buck harvest has been more rapid in some states than others. Hunters in a handful of states still take high percentages of yearling bucks, but even the trend is moving in the right direction.”
A balanced age structure allows for a natural social order. There should be yearlings, teenagers and adults. All play a role in whitetail society.
“If there are no mature bucks in the herd, then the social structure is missing a piece,” Adams said.
When there are no mature bucks in a herd, yearling bucks will take care of the breeding. But that’s likely to lead to smaller racks.
The problem isn’t one of genetics; it’s about stress, Adams said.
The rut takes a lot out of bucks, young and old. When a mature buck is recovering from the stress of the rut, all of the nutrition he takes in during winter and spring goes toward recovery. Come summer, his body is ready to focus on growing antlers.
Yearlings run down from the rut need nutrition to recover and grow their bodies. Those two considerations come before growing antlers, which can get short-changed.
“Those young bucks are still growing and need more nutrition for putting on body weight,” Adams said.
When the age structure of a herd is normal, yearling bucks will do less breeding. That allows them to use more nutrition for growing to their maximum potential.
In addition to that physical benefit of having a varied age class of bucks, there could be other social implications as well.
Studies have shown there are up to 50 pieces of information contained in secretions from the forehead glands of bucks, Adams said. And there are certain hormones that are present in greater volumes in older bucks versus young ones. What’s more, he said, there are hormonal differences in dominant mature bucks as opposed to just mature bucks.
“All of this is important in the social communication of the herd,” he said. “We don’t know what it all means to the deer, but we’re studying that constantly.”
In studies of different herds, where one features a complete, healthy age structure and another is heavily skewed toward yearlings, Adams said researchers have found the mature bucks in the healthy herd rubbed and scraped as much as ten times more than bucks in the other herd. And they started leaving sign about a month earlier.
“As hunters, we get to see that sign and track it as part of our hunt,” he said. “Seeing that sign certainly makes hunting more enjoyable.”
Also, bucks in more natural herds are far more vocal than in skewed herds. As a result, bucks in the natural herd are more likely to respond to rattling and calling.
“It’s something they hear all the time, so it’s natural,” Adams said.
While there are certainly benefits to having a balanced buck-to-doe ratio, Adams and Stedman agree it’s not a good idea to manage with sex ratios as the driving force.
“I don’t get caught up with the sex ratios,” Adams said. “Don’t have too many does, or too few, and protect yearling bucks. If you do that, the sex ratio will come out okay.”
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This article was published in the October 2014 edition of Buckmasters Whitetail Magazine. Subscribe today to have Buckmasters delivered to your home.