Buckology: The New Science of Deer Hunting

width=500 Until we can successfully transplant a human head onto a buck’s body, nothing we say about whitetail behavior amounts to more than an educated guess. Dr. Karl V. Miller, a deer expert whom I talk with regularly, and I have arrived at an agreement that allows him to preserve his integrity as a scientist and allows me to preserve my sanity. It is understood that his response to any question about what a deer will or won’t generally do begins with the following: “It all depends on the situation…” In short, we’ll never know it all. But our knowledge of the whitetail continues to advance. The latest studies, presented here, reveal new insights that debunk much of what we used to hold as deer gospel. This science will also improve the way we hunt. VISION The Old: Once a deer sees you, even from a good distance, the game is over. ** The New:** We already knew quite a bit about how deer view the world: Deer vision, like our own, is a function of rods and cones; deer can see extremely well in low light; and deer have only two types of cones (blue and green-yellow), whereas humans have three (blue, green, and red). Their color vision is of lower quality generally and narrower in overall ability to differentiate certain hues. Researchers believe that deer see blaze orange as a shade of gray. However, their blue cones enable them to see that color distinctly. So the hunter who wears blue jeans and a camo shirt rather than full-body blaze orange has got it backward. He is more visible to deer and less visible to fellow hunters, which makes it a safety issue as well. Now, here’s where it gets interesting: A deer’s ability to distinguish detail is horrendous. Using a hand-raised doe named Nellie and “targets” of black-and-white bars of varying sizes, Dr. Karl V. Miller, professor of wildlife ecology and management at the University of Georgia, and his students measured Nellie’s visual acuity. A human with excellent visual acuity has 20/20 vision. Miller discovered that Nellie sees detail at about 20/100. In other words, if you are 20 feet from a deer and remain motionless, the deer can resolve the details of your appearance no better than a human observing you from 100 feet. What This Means for Hunters: Two things: One, a deer couldn’t care less what camo pattern you’re wearing. If it breaks up your outline, it has done its job. Two, when a whitetail stares straight at you and snorts—that is, when you are certain you’ve been busted—do not throw in the towel. If it is your movement that has alerted the animal, it’s possible that the deer has not yet figured out what you are. If you freeze, you basically disappear again. Unless the alarmed deer smells you, it may relax after a minute, giving you a second chance. Which means the game isn’t over until the deer flees. Bonus: Tree-Stand Consealment Deer pupils are horizontally slit, which, along with features such as the distribution of rods and cones, gives them a completely different kind of vision from our own. First, deer can take in a tremendously wide field of view at a glance, with no eyeball movement needed. Second, their orbs are designed to pick up danger where it will do them the most good—at a distance. Third, the slit naturally orients their eyes to pick up movement at or just below the horizon, the place from which a predator is most likely to appear. Miller maintains that deer eyes are much less adept at picking up movement above that horizon line. So although hunters can never get away with much movement around a deer, they can get away with more movement in a high tree stand than on the ground. HEARINGA The Old: Deer can hear an acorn drop 100 yards away on a calm day. The New: More studies conducted by Miller and researchers at the University of Georgia show that deer hearing is actually quite similar to ours. Although deer can hear into the ultrasonic range, their hearing is most sensitive to moderate frequencies, between 4,000 and 8,000 Hz. Humans hear best at roughly equivalent frequencies, between 2,000 and 5,000 Hz. And a deer’s optimum hearing zone happens to overlap with the frequencies of human speech—levels comparable with those of many deer calls, especially grunts. The University of Georgia study only tested the inner properties, without taking the sound-gathering capacity of the whitetail’s large ears into account. Miller thinks they may increase a deer’s ability to pick up sounds, but he says the more important function lies in helping the animal pinpoint the source of the sounds. What This Means for Hunters: If you’re calling or rattling, you probably ought to be doing it more loudly than you previously thought. Sound does not travel well in natural environments to begin with. Gino D’Angelo—at the time of the study, a student of Miller’s—tested a variety of commercial grunt calls and found that the strongest frequency for virtually every grunt was in the range of 3,000 to 4,000 Hz, aligning with the optimum hearing range of both deer and humans. So if you’re using a high-pitched call (one with a high frequency) like a fawn bleat, you probably really need to call loudly. D’Angelo also found that deer are quite attuned to, and alarmed by, low-pitched sounds, which they can pick up at considerable distance. In other words, your truck door going thunk! may well clear deer out of the woods before you’ve even shouldered your pack. Bonus: Why Bleats Work In all his years around deer, Miller says, he has never heard an estrous bleat in the woods. He acknowledges that commercially manufactured estrous-bleat calls, such as cans, are successfully used by hunters but believes they work for reasons other than those advertised. “To me, estrous bleats sound very close to a fawn bleat,” says Miller. “It might be that bucks are responding because they know that a bleating fawn usually means there’s a doe nearby.” RUT MOVEMENTNo The Old: There are practically as many theories about buck movement during the rut as there are hunters. Take your pick. The New: Now we know why hunters hold such varying views—everybody’s wrong…and everybody’s right. There’s no such thing as a “typical” buck. Different bucks, even those of the same age in the same area, have widely varying patterns of movement during the rut. “We found that some bucks have big home ranges and some have much smaller ones,” explains Texas A&M University-​Kingsville biologist Randy ­DeYoung, who fitted 50 deer with GPS collars and tracked their movements as often as every 15 minutes. “Some bucks are quite active during the rut, while others move little. And we see no connection between range size and activity. You’ve got bucks with small ranges where they’re so active they’re practically doing laps. And you’ve got bucks with large ranges that move very little. What this suggests is that there is a variety of successful breeding strategies.” What This Means for Hunters: If you are hunting a particular buck, and not simply setting up in an area you believe is attractive to deer, you’d better study his personality at every opportunity for clues about his movement behavior. Also, it’s now official that you are being lied to whenever someone begins a statement with: “Usually, a big buck will…” DAILY MOVEMENT The Old: Whitetails are most active at dawn and dusk. The New: True. But you may be more likely to see a whitetail during the morning. Mark Conner, a biologist at DuPont’s Chesapeake Farms in Maryland, had graduate students from the North Carolina State University Fish and Wildlife Program put GPS collars on 18 bucks, registering their movements as often as every 20 minutes. To no one’s surprise, the studied deer moved most at dawn and dusk. But the peak of evening movement occurred after legal shooting hours, whereas the peak of morning movement took place during legal hours. What This Means for Hunters: “I would be inclined to plan my hunts for the morning,” says Conner. “But the deal might not be as straightforward as it seems at first. For one thing, it’s generally easier to figure out where deer are bedding than where they’re headed to eat. That favors afternoon hunters. It’s also generally easier to set up on bedded deer than on moving deer. A morning hunt takes a lot more planning, because you’ve got to get to your tree stand without bumping deer. In some cases, such as when you don’t own the property you would need to cross to set up undetected, it’s not feasible. However, if you can find a way to set up undetected, morning hunts are definitely the way to go.” EXCURSIONS The Old: Excursions? Huh? The New: Conner found that most of his GPS-collared bucks made one or more straight-line “excursions” outside their home ranges during the pre-rut and rut, lasting from six to 24 hours. During the three weeks before the rut, 40 percent made an excursion. During the three weeks of the rut, 58 percent did. The straight-line nature of the movement led Conner to believe that the bucks were traveling with receptive does. Had they been seeking does, the routes would have been more wandering and circuitous. To his knowledge, no one else has documented this phenomenon. What This Means for Hunters: If you’ve been hunting an area enough to become familiar with its deer and see a buck you haven’t seen before, there’s a strong possibility that he’s on an excursion. Act now if you want the buck. You may not see him again. DENSITYwidth=300 The Old: If you don’t see many deer, it’s because there aren’t many deer for you to see. The New: Wrong. When deer are hard to find, your best bet is probably to hunt hard and hunt in the remotest area you can find. In a study conducted by Penn State and the Pennsylvania State Game Commission, does in two different areas were radio-collared and monitored. One area was rugged big woods with limited road access. The other was fragmented, rolling country that included both woods and agricultural land; it also had better hunter access. When the hunting season was over, according to Kip Adams, a biologist with the Quality Deer Management Association, which donated some of the collars for the study, the numbers told an interesting tale. Hunter-induced mortality was significantly higher in the easily accessed area, where 14 of the 64 available does were taken. In the remoter area, just three of the 77 available does were killed. A further wrinkle: In the easily accessed area, the location of the deer’s home ranges had little effect on which were taken. In the more challenging area, deer with home ranges close to the road were the ones taken by hunters. What This Means for Hunters: Two things are immediately evident, according to Adams. First, even in Pennsylvania, a state of diehard hunters (many of whom have complained that they’re seeing fewer deer), plenty of deer remain, and plenty of deer elude hunters. Second, Adams finds hope in knowing that just because you’re not seeing deer, it doesn’t mean they aren’t there; it could mean the deer are heavily pressured, making them that much harder to hunt. Plus, the higher rate of survival among deer in the remote area tends to reinforce a long-held belief: To succeed where others fail, go where others fail to go. BREEDINGBig The Old: Big, dominant bucks do most of the breeding because they win most of the fights. The New: Good news for dweebs! Subordinate bucks may sire just as many offspring. In a multiyear study from 1991 to 2003—and in ongoing studies started in 1999—in which DNA testing was used to determine paternity, DeYoung found that younger bucks managed to breed does, even in an area with a lot of mature bucks. The difficulties in establishing parentage of deer populations are enormous. It’s impossible to know how many does a buck mated with, as not all couplings result in pregnancy; how many of the fawns produced died before making it to the 6-month mark at which testing for parentage occurred; and whether all the bucks and does in a large area had been caught and tested. Nevertheless, DeYoung feels confident enough to assert some new ideas. “So-called dominant bucks don’t breed as much as you would think,” he says. “Our ‘grand champion’ only fathered 12 documented offspring over a five- or six-year period, and he wasn’t a trophy deer antlerwise.” This buck and others probably sired more than the documented number of offspring, DeYoung adds, but he doubts it was significantly more. “About a third of our studied bucks sired at least one fawn a year. It’s probably substantially higher than that, given fawn mortality and bucks that might have sired fawns that we never succeeded in getting DNA from. But the bottom line is that dominance is not as big a factor as we thought, and even younger bucks sire a good portion of the fawns.” What This Means for Hunters: This has more implications for those trying to grow big deer on a given parcel of land than for hunting. If you’re trying to influence the gene pool by harvesting smaller bucks, you’re basically spitting into the wind. “If you manage very intensively on a small, high-fence area, maybe, given enough time [you could influence genetics],” DeYoung says. “But on most areas, it’s difficult to exert enough pressure to actually change the genetics of a wild, free-ranging deer herd. You can’t control which bucks breed, how many fawns they sire, or the other half of the equation: the doe’s contribution.”