Deer management FAQ

Why institute a deer management program?

The District recognizes white-tailed deer as an important part of Will County’s biodiversity. However, high density levels of white-tailed deer in many of our preserves are damaging the health and well-being of our woodlands, savannas and prairies. If left unmanaged, this will result in rapid and dramatic changes to these areas.

It is understandable that the decision to manage deer may cause some public concern. However, the Forest Preserve District has made this decision based on extensive research, consultation and discussion. If deer are left unmanaged, their large numbers will cause dramatic changes to the District’s ecosystems, resulting in irreversible damage and potential loss of species.

What is the impact of overbrowsing by deer?

Excessive overbrowsing:

• Shifts dominant canopy tree species, including oak and hickory trees. This means fewer nesting places for birds, and a loss of natural food sources and fewer areas of protection for countless other species, including the deer themselves.
• Reduces ground layer vegetation abundance and diversity. Deer consumption of seeds and flower buds decreases and, in some cases, eliminates the ability of plants to reproduce. This takes away important food sources for other species. A lack of ground cover also provides little protection for smaller animals, and can contribute to nearby flooding as rich top soil is washed away and erosion is accelerated.
• Increases sedimentation in surface water due to advanced erosion. Overbrowsing causes erosion and runoff in water sources, changing the quality and composition of streams and creeks.
• Affects the availability of food sources for wildlife, threatening the well-being of the deer themselves and other animal species. With drastic changes in the abundance and diversity of plants will come the reduction or elimination of animals that count on those plants for food and cover.

How do management practices align with the Forest Preserve’s mission?

The Forest Preserve’s mission dedicates it to the protection and conservation of the natural heritage of Will County. As a steward of the environment, the Forest Preserve District is taking a proactive approach to protect, maintain and restore the balance and sustainability of our natural areas. This includes the health of deer as well as other species. Deer herds that reach high density levels tend to be in poor health, and are prone to cyclic population fluctuations and catastrophic losses. Excessive deer populations are also incompatible with human interests and land-use practices. These can include public safety risks through increased deer-vehicle collisions, as well as transmission of disease such as Lyme disease. Losses related to agricultural production are also a consideration.

What methods of management have been and will be used by the Forest Preserve District?

After months of discussion at the committee and full Board levels as well as at other public meetings, the Board of Commissioners in September 2010 approved the use of sharpshooting to reduce the deer herds in select preserves.

Sharpshooters consist of Forest Preserve police officers as well as volunteers who have gone through a comprehensive screening and certification process. Individual preserves included in the deer management program will close at 3 p.m. Monday through Thursday on days when culling is taking place. Sharpshooting will begin after the preserves are closed.

What is the desired deer density?

The intention is to reduce deer populations until the negative impact to our preserves is alleviated, and then to maintain deer populations as needed to have a balanced ecosystem. Utilizing sharpshooting, the District hopes to reduce the deer number close to a target density of 10 deer per square mile. Most of our preserves are well above this maximum level. Regular assessment of our preserves’ vegetation will allow us to adapt the program as needed. The District’s management program will in no way ever pose a threat to the existence of deer in Will County.

When does the deer management program begin?

The District’s deer management program begins annually after Thanksgiving.

What process is used to select preserves for culling?

Preserves where culling will take place are selected each year using a variety of criteria. Three of the most important are: browse damage, sensitivity of the flora and deer density. After selecting which preserves should be included in the deer culling program for the year from a resource protection perspective, other criteria such as public safety must also be met. Consistent management is key to the program's success, so generally the same sites are managed each year.

The Forest Preserve relies on a variety of methods to determine the damage deer are doing to natural communities. These involve deer counts from a helicopter to determine deer herd density and the monitoring of at least eight permanent single species plots per management area. These plots are monitored annually in the summer to determine deer browse rates.

With public safety being the highest priority, culling will not take place in preserves where a sufficient buffer from outside properties cannot be realized.

When will these preserves close early for the program?

Preparations for the Deer Management Program begin in the fall, but the preserves selected for the program will not close early until after Thanksgiving. Preserves involved in the program will close at 3 p.m. on Monday through Thursday to protect preserve users. However, a preserve included in the program will be closed only when deer culling is scheduled at that location for that day. Normally, the preserves would close at sunset, which is around 4:20 p.m. in December. Because winter has the shortest days of the year, the inconvenience to preserve users is somewhat mitigated. While signs posted at the preserves read that the program will continue through March, typically the program ends in February. The program can extend into March depending on weather conditions and the number of deer being culled in a particular year. Individual preserves return to normal hours based on when the desired number of deer are culled.

How do you ensure that the public is kept safe?

Public safety is priority #1. To ensure a safe program, sharpshooting is implemented in full compliance with IDNR regulations, and in accordance with the risk management guidelines set forth by the District’s insurance administrator, the Park District Risk Management Agency (PDRMA).

Sharpshooting occurs starting at dusk when the preserves are closed, with safety buffers of at least 100 yards from the preserve boundary. Firing stations have been selected to ensure shooting always occurs in a safe trajectory over a distance of approximately 50 yards (the same distance required for IDNR sharpshooting certification). Sharpshooters shoot into the preserve, and not toward or beyond the preserve boundary. In addition, all bait stations must be approved by IDNR.

Signage will be posted at the entrance to the preserves where sharpshooting activities are scheduled to occur. Operational meetings are also held at the beginning of each night’s culling shift to review safety considerations.

What do you do with the deer that are managed?

Once deer have been culled, they are field dressed at another location and transported to an IDNR-approved, licensed facility to process the meat. The IDNR requires the meat to be donated to local food pantries.

Other than just seeing some vegetation impacted, what actual studies have been done and what were the results?

As early as 1997, the District became aware of significant changes in forest structure upon completion of a vegetation study which compared two periods in time, 20 years apart. Additional browse studies have been conducted at select sites. These studies have documented the negative changes in forest structure related to overbrowsing due to the excessive deer population.

One study of Large-Flowered Trillium at Messenger Woods Nature Preserve documented significant browse impacts affecting the number of Trillium and how well they were reproducing. The most dramatic evidence for these findings was recorded in 2007 when no flowering Trillium were observed in two study plots exposed to deer browse while an abundance of flowers existed in fenced study plots protected from deer browse.

Another study in seven of our highest quality woodlands demonstrated significant recovery of the vegetation after only three years of data collection, including the increasing abundance of desirable native trees such as oaks and hickories within study plots protected from deer browse.

In 1993, the District implemented a deer census program to allow the deer population levels to be correlated to vegetation monitoring results. This data clearly shows that white-tailed deer exist at densities well above levels that can be sustained by the preserves without resulting in severe degradation of the ecosystem. Since deer populations can double in size every two to three years, the impact will be exponential if not addressed in an ongoing management program.

Which other organizations conduct deer management?

As of the 2022-2023 season, five county forest preserve/conservation districts, two arboretums/botanical gardens, two federal facilities, one park district and one homeowner/property owner association across Lake, Will, Winnebago, Cook, DuPage, Jo Daviess and Kane counties received deer population control permits from the IDNR.

Can’t the District feed the deer to offset the loss of vegetation?

State law prohibits the feeding of deer, and feeding will not solve the problem. Deer will continue to reproduce, and studies have shown that feeding actually serves to concentrate deer in small areas year after year where animals do serious and potentially irreparable damage to native vegetation. This further reduces the carrying capacity of the area and makes deer increasingly dependent upon supplemental feed. Moreover, decades of research have shown that feeding leads to increased disease risk, long-term habitat destruction, increased vehicle collisions, habituation to humans and alteration of other deer behavioral patterns. It can also increase winter starvation by luring more animals than the feed can support.

Can’t the deer be relocated?

Deer often experience physiological trauma during capture and transportation, and relocation often results in high mortality rates for deer. Mortality after relocation within the first year has ranged from 25 to 89 percent from a wide range of causes.

Additionally, the identification of large blocks of landowners willing to serve as receptor sites in urbanized areas and the resolution of liability concerns associated with relocation make relocation extremely difficult. Many relocated deer will settle in suburban or agricultural habitats and create nuisance problems.

What has been the progress of the deer culling program so far?

To read the program summary reports for the previous years that the program has been held, visit the printable reports and brochures section. Deer culling was not conducted in 2012-2013.