1/2/2020 8:56:23 AM
William T. McKinley is MDWFP’s Deer Program Coordinator.
Imagine you supply widgets for an entire state, and you have a store in every county. Your statewide inventory is about 1.4 million widgets, and that inventory has declined slowly for the past two decades. You know that 200,000 widgets were purchased statewide last year and this number has been declining significantly from year to year. How would you get to the bottom of the decline? Is the decline happening uniformly across every store in every county? Not likely. Some stores could be increasing their sales, but significant drops in other stores are causing an overall decline. Therefore, you need data from every store so you can ascertain where the reductions are happening.
The above scenario is similar to managing Mississippi’s deer herd. Our deer herd varies across the state in density, body size, antler size, and timing of breeding. Many factors contribute to this variation, including weather, habitat management (or lack thereof), soil fertility, predators, and disease. Statewide data suggests a declining deer herd. However, herds might not be declining in some areas, possibly areas that include multiple counties.
Mississippi gains statewide deer population estimates through the Downing Population Reconstruction Method. This method uses the total statewide harvest estimates of antlered bucks and antlerless deer. It applies the age ratio of harvested deer from the Deer Management Assistance Program (DMAP) to work backward for a population estimate from five years ago. The most recent population estimate is 1.48 million deer in 2014. This method is not perfect, but it is currently the best method available (deer tend to not stand still and be counted).
MDWFP receives statewide deer harvest estimates annually from a phone survey of licensed hunters. Each summer, a percentage of hunters with a valid hunting license is called and asked questions regarding hunting effort and harvest of all game animals from the previous season. The reported harvest is extrapolated to include the total number of licensed hunters, both resident and nonresident. These harvest estimates do not include game harvested by license-exempt hunters, such as those under 16 and over 65. There is currently no valid method to determine the number of license-exempt hunters in Mississippi, nor to estimate their harvest.
The statewide deer harvest has declined sharply over the past two decades, with the steepest decline happening in the last few years. Total deer harvest has declined about 125,000 deer, or about 40%, since 2010 (see chart below). First, we must assume that the decrease in harvest directly correlates to a reduction in the total number of deer on the landscape. Statewide hunter effort is measured with the phone survey, by comparing the number of days hunted to the entire harvest. The energy required to harvest a deer in Mississippi has increased in correlation to the decrease in harvest. This data supports a declining deer herd.
Several theories exist regarding the cause of the decline:
WILD HOGS
The wild hog population in Mississippi has exploded over the past decade. The estimated harvest of wild hogs now exceeds the estimated harvest of deer in Mississippi (see chart, page 15). Wild hogs compete directly with deer for food resources, spread disease that could reduce fawn production, and eat fawns when they find them.
HABITAT CHANGES
Landscape-level habitat changes have resulted in less deer forage across the state. An example is the number of pine plantations in need of thinning. A depressed pine market has led to many stands well past the need for thinning, keeping sunlight off the forest floor, and reducing the total amount of deer forage available.
DISEASES
BLUE TONGUE: Epizootic Hemorrhagic Disease (EHD), or Blue Tongue, takes a toll on deer herds across the country annually. EHD is considered one of the most important endemic infectious diseases in white-tailed deer in the Southeast. Outbreaks occur every year and are highly variable in severity. Mortality of the population is usually less than 25%, but could be 50% or greater. However, these percentages are hard to gauge, as many deer that die from the disease are never found. It tends to occur on about five-year cycles in areas across Mississippi.
AFLATOXICOSIS: This is a disease caused by a fungus that naturally grows on corn. Studies have shown that if corn is wetted and the temperature is above 62 degrees, aflatoxin can increase to levels capable of negatively affecting fawn production in deer and killing wild turkeys, along with impacts on many other wildlife species.
CHRONIC WASTING DISEASE (CWD): The discovery of this disease in 2018 in the South Delta and North Mississippi has the potential to negatively affect Mississippi’s deer herd more than any other factor in recent history. Studies from other states show that reducing deer density through a variety of methods has the most significant impact on keeping prevalence low and slowing the spread of the disease. In other states, managing CWD includes liberalizing deer harvest in each county where the disease is found. Success is determined through monitoring total harvest and disease prevalence in each county. It is critical in CWD management that MDWFP has reliable harvest estimates from each county.
All these factors likely contribute to the decline in Mississippi’s deer herd. But where is the decline occurring? Uniformly across the entire state? Not likely. How does MDWFP determine in which counties or regions the decline is occurring? Currently, we do not know. MDWFP needs county-level deer harvest data. From this data, trends would show fluctuating harvest in counties and regions of the state. MDWFP could begin addressing the regions with declining harvests, without impacting regions where the deer herd is stable.
The system to gain this county-level harvest data already is in place. It is Game Check. Harvest reporting is already mandatory for wild turkey but is voluntary for deer. It requires legislation to become mandatory for deer, and Mississippi is the only state in the nation that does not require mandatory tagging or reporting for harvesting big game.
To report a deer, hunters can go online or use the MDWFP app on their smartphone (www.mdwfp.com/wildlife-hunting/game-check/deer-game-check). If using the app, the hunter selects the county harvested, private or public land, buck or doe, weapon type, and a description of the antlers on bucks. The entire process takes less than one minute and can be done in areas with little or no cell phone service.
With our state facing new challenges to our natural resources, MDWFP needs mandatory reporting more now than ever to manage our deer herd. Concerned hunters have always been the greatest asset to Mississippi’s wildlife. We ask for your support in this conservation issue.
William T. McKinley is MDWFP’s Deer Program Coordinator.
