Topic Area: Wildlife Management
Geographic Area: Wisconsin, U.S.A.
Focal Question: Has Wisconsin’s Deer Management Program been successful in achieving a healthy and sustainable herd population?
1) Wisconsin Department of Natural Resources Website:
2) Wisconsin Department of Natural Resources, “Wisconsin’s Deer Management Program: The Issues Involved in Decision-Making” Second Edition (1998).
3) “Hunting license sales highest in five years,” DNR News: November 21, 2000.
4) Patterson, Jen. “Wisconsin in the forefront of strategies that have allowed wildlife to recover and thrive” DNR News: Special Edition, Dec. 20, 1999.
5) Martino, Sam. “Village to continue reducing deer herd,” Milwaukee Journal Sentinel, June 7, 2000.
Reviewer: Russell J. Casper, Colby College, ’02.
In the 1800’s, wildlife in the area that is now Wisconsin was suffering. Westward expansion and settlement brought about drastic changes in the natural equilibrium and severe over-harvesting. As a result, the population of various animals, including the white-tailed deer, decreased dramatically. The problems persisted until dangerously low population levels prompted the state government to take action. According to the Department of Natural Resources (DNR), at the turn of the century the white-tailed deer population was estimated at less than 500,000 nationwide. Subsequent hunting regulations were able to stop this disturbing trend, precipitating a rapid rise in the deer population. In 2001 the DNR estimated that the Wisconsin herd alone contained 1.65 million deer.
Of course, saving deer from extinction was only the first step of deer management in Wisconsin. By rebuilding the population of deer and eliminating its natural predator, the wolf, deer were allowed to expand virtually uninhibited. Therefore, as the white-tailed deer began to thrive again, the state was forced to manually control the population. The system that was created has undergone a variety of changes, increasing the program’s precision and complexity. The current system consists of 3 regions, which are in turn divided into 132 separate deer management units.2 Each of these units is individually monitored to gather the pertinent information for predicting the deer population and calculating overwinter population goals.
In order to calculate the efficient population goal, the DNR attempts to balance the costs and benefits associated with a high deer population. The DNR first considers deer’s importance to society. Deer are a valuable resource for hunters and non-hunters alike. Non-hunters value deer for their natural beauty. The DNR reports that a study conducted by the University of Wisconsin Madison found deer to be the most popular form of wildlife among non-hunters. In 1996, 2.3 million state residents and 423,000 out-of-state visitors participated in observing, feeding and photographing wildlife.2
Hunters also value deer very highly. According to DNR estimates, 694,111 deer hunting licenses were sold for the 2000 season.3 Information gathered by the National Survey of Fishing, Hunting and Wildlife-Associated Recreation estimated that each hunter spent an average of $1,300 during the 1996 season. Assuming that this level of spending has remained relatively steady, hunting generates over 1.2 billion dollars in sales annually.2 In addition, this figure does not into take into account costs associated with processing deer, or the wages and salaries of wildlife management workers.
These benefits are then balanced with the factors that support a smaller deer population. The biological carrying capacity, which is the maximum number of animals that can survive on the land, is one of the main limiting factors of deer population. In addition, the DNR considers a variety of social impacts. Costs associated with agricultural damage, forest and plant damage, the possibility of spreading disease and deer-vehicle collisions constitute most of what is referred to as the “social carrying capacity.” In general, the social carrying capacity refers to the maximum number of deer that people are willing to tolerate.
Using these criteria, the DNR sets a population goal that will hopefully accomplish their mission of creating a healthy, sustainable herd. Although population goals vary according to individual deer management units, the DNR estimates that a population of 65-70% of the estimated biological carrying capacity will allow them to meet their goals.2
Based on the difference between the estimated deer levels and the DNR’s overwinter population goals, annual hunting quotas are established, which in turn regulate the number of deer permits that are available. Unfortunately, because of uncontrollable factors, most notably the weather, the exact relationship between the number of permits issued and the total harvest is not known. For example, poor hunting conditions or an unforeseeably mild winter can result in post-hunt deer population that is above the target level. To avoid an insufficient harvest, in 1996, the DNR instituted the option of additional herd-control seasons, referred to as “Zone T” seasons. If it appears that a deer management unit will be unable to achieve its population goal through the regular gun, bow and muzzleloader seasons, Zone T hunts can be offered to increase the harvest. One free Zone T permit is issued with the sale of any hunting license, and is valid for all deer hunting seasons, including any Zone T hunt.
According to DNR estimates, the population of deer has risen from 892,000 in 1997 to approximately 1.65 million in 2001.1 This drastic increase has come despite the DNR’s best attempts to increase the annual harvest. Notwithstanding relatively large harvests, including the record-breaking harvest of 618,374 in 2000, the post-harvest deer population has been drastically above the overwinter population goal that, according to “Deer Management for 2000 and Beyond”, would be approximately 740,000.
As a result of the excessively abundant deer population, vehicle killed deer have increased from 18,200 in the late 1970’s to 47,555 in 2000, according to DNR figures.1 Although increased miles driven can account for much of this increase, DNR studies have revealed that deer killed by vehicle collisions per miles driven has nevertheless increased.
In addition to increased vehicle-deer collision, other costs associated with a high deer population have risen. For example, the health of Wisconsin’s deer population, and its possible effects on human health, has been a topic of concern. As a result, deer have been tested for Bovine Tuberculosis (TB) and Chronic Wasting Disease (CWD). The presence of TB is of particular interest due its ability to affect human health. Despite the concern, the DNR has not found any instances of TB, and only isolated cases of CWD. The increased high deer population has also prompted individual communities to take further action. In order to prevent nuisance behavior, like vehicle-deer collisions and costly damage to agriculture and plant life, communities are permitted to, and occasionally do, hire the services of sharpshooters to trim the herd.5
Clearly, determining the appropriate deer population is a difficult proposition, involving a variety of considerations. Implementing these population goals has proven even more difficult. Given the inability to precisely predict the annual harvest, the DNR has implemented possibilities for additional population reduction. However, recent attempts to reduce the deer population to the desired level have failed. As a result, Wisconsin has been forced to accept various costs that are associated with a high deer population. Although the herd does not appear to be dangerously high, there appears to be plenty of opportunity to decrease the population while increasing efficiency.