Deer Management 2009
November 04, 2010
Top researchers gathered in Virginia to discuss the status of whitetail deer and deer hunting in America.
The Southeast Deer Study Group meets once a year to present and discuss the latest deer research. Though the group's name implies a regional meeting, for the past 32 years it has been far more than that. This year the Virginia Department of Game and Inland Fisheries and the Conservation Management Institute at Virginia Tech hosted this professional conference in Roanoke, Virginia, and 133 deer scientists from all over the country presented 37 papers on whitetail deer.
As always, Bowhunter Magazine was there, and our purpose in attending is to bring you the latest deer research that impacts you and your hunting. We can't report on all the papers (it would take too much space), but here is our annual summary of the "good stuff."
Responsive Management is a wildlife survey company in Virginia, and their president, Mark Duda, presented some interesting data on public attitudes about hunting (spanning 26 years). For example, our motivation to hunt has changed. In 1980, 43 percent of hunters listed "meat" as a primary reason to hunt, but in 2006 that had dropped to only 16 percent. Duda noted that hunting participation is decreasing because of an aging society, less access (and less land to hunt on), and less free time (our lives are more structured than they once were). In addition, urbanization is diluting the hunting culture. Note that 92 percent of all youths who hunted in the past year came from a hunting family. Since hunting families are decreasing, the future does not look good. To continue the urbanization problem a bit further, Clayton Nielsen from Southern Illinois University talked about the expansion of human development and the related impacts on deer management. Consider the fact that anything within 300 yards of a human structure is a hunter-restriction zone in Illinois. That may not sound too bad, but in fact, this restriction eliminates 31 percent of Illinois from hunting. This is a sign of the times, and this phenomenon is only going to get worse in most states.
We are also seeing a huge change in harvest trends. Kip Adams, with the Quality Deer Management Association (QDMA), presented data showing that from 1999 to 2005 the nationwide percentage of yearling bucks in the harvest declined from 51 percent to 45 percent. Doe harvests increased by 10 percent, and buck fawn harvests declined. Twenty-two states now have some form of antler-restriction program. Indeed, times are changing.
And, relative to urban deer hunts, look at what is happening in Howard County, Maryland (between Baltimore and Washington, D.C.), where there are over 1,000 people per square mile. There, Phil Norman has been running various hunts on county parks since 1998. While animal-rights protestors oppose the hunts and claim to represent all citizens, a 2008 phone survey showed that 83 percent felt that management hunts were the only viable option to curtail deer numbers. Considering the location, this represents huge support for hunting and for the safety of such hunts.
A company called Eccologix presented data showing why the urban public likes these bowhunts. They work! The next time an animal-rights group tries to prevent an urban hunt in your town, show them some data. In 2007, Eccologix-certified bowhunters in a suburb of Philadelphia took 568 deer, of which 551 were does. Since harvesting does lowers deer numbers, and that is the objective in these urban hunts, it is obvious that bowhunters can get it done.
One final bit of information on the human dimensions side -- Susan Guynn talked about a course she now teaches at Clemson University designed to introduce women to hunting. Consider that since 1991 hunting license sales in the United States have decreased by 11 percent but women participation in hunting is up nine percent. Sounds like it's the right time for that college course!
Now, let's look at the deer. Researchers at North Carolina State University and Chesapeake Farms in Maryland presented a very interesting paper on intracranial abscessation. Before you turn the page, hear me out on this one. Intracranial abscessation is an abscess on the outer linings of the brain caused by bacteria which leads to nine percent (nationwide) of all the natural mortality of bucks, especially older bucks. In a five-year period, they found abscesses in nine (35 percent) of 26 necropsied bucks that were over 2.5 years of age on Chesapeake Farms on Maryland's Eastern Shore.
However, they did not find the infecting bacteria in 10 bucks examined from the King Ranch in Texas, but it's not known why. Somehow the bacteria gets from the environment into the buck's brain, and it is believed that an injury to the base of the growing antler in early fall, or a head injury during rutting activity, may be the cause. I talked to Mark Conners, wildlife biologist and manager of Chesapeake Farms, and he noted that there is irregular antler casting (the timing when antlers drop) at Chesapeake Farms, and this bacteria and subsequent skeletal damage may be the cause.
He notes that some sheds have a foul odor -- indicating infection -- and some also have parts of the pedicle from the skull still attached. Abscessation is an interesting phenomenon and could impact efforts to get bigger bucks via management. I'm sure we will hear more about this disease in the future, and Bowhunter will bring it to you.
Remember the huge outbreak of hemorrhagic disease (HD) two years ago? Researchers in Virginia looked at factors that may allow the prediction of HD outbreaks. A midge transmits the disease, and being able to predict the insect's emergence is the key. In Virginia, a low June rainfall means a better chance that there will be a late-summer outbreak of HD because that creates favorable breeding sites for the midge and diminishes food and water sources for deer, thus increasing stress.
Texas researchers at the Caesar Kleberg Wildlife Research Institute went to the King Ranch to learn if buck movement patterns in the rut were correlated with age, antler size, and body condition. They tracked 30 radio-collared bucks (at 15-minute intervals) and expected to find that older bucks would have larger home ranges, giving them increased contacts with does. However, the study showed that home-range size in the rut did not vary for bucks of different ages. They concluded that "The lack of strong relationships between several physical characteristics and movement patterns of bucks suggests large individual variation."
Speaking of movements, Jeff Kolod-zinksi of the University of Georgia followed 15 adult does in parts of Maryland where there were high deer numbers but near equal sex ratios. They found oscillating trends with three to five peaks every two weeks. These peak times differed for each doe, so moon or weather was not the cause of these movements. They did see 9 of 10 does making an excursion from their home range that lasted one full day during the rut and suggested that
they were looking for potential mates even when mature males were abundant.
Another study done in Oklahoma showed that moon phase, temperature, wind, relative humidity, and barometric pressure had little to do with deer movements. While other researchers in South Texas showed that hot temperatures definitely reduced daytime movement and forced deer to feed at night. What impacts deer movement in one area may be different in another area.
Finally, the evidence showing high impacts of coyotes on deer is increasing east of the Mississippi River. Research in Georgia compared two large areas, one where 23 coyotes and three bobcats were removed between January and August, and another area nearby where no predators were removed. In September, the fawn-to-doe ratio was 0.72 in the removal zone and 0.07 in the non-removal zone. Obviously, coyotes have an impact on fawn survival in that area.
There's more, but space won't allow us to cover it all. The good news is that next February 29 these deer biologists will meet again in San Antonio, Texas, to add to our knowledge of whitetails. These meetings are open to anyone who wants to register, so if you're interested, you can get details from the Texas wildlife agency website (www.tpwd.state.tx.us). See you in Texas!