White-Tailed Deer and Ecosystem Management

Deer in DuPage County

Late 1800s to Early 1900s

The need for lumber and farmland triggers a decline in the amount of habitat for deer. The loss of habitat and unregulated hunting almost eliminate white-tailed deer from Illinois.

Middle 1900s

Conservation laws halt unscrupulous hunting, and the Illinois Department of Natural Resources begins to restore, protect and manage deer habitat. Deer populations are further boosted by DuPage farms, which guarantee plentiful sources of food.

Late 1900s

Deer populations continue to rise but do so unchecked: Because of the unregulated hunting practices of a century ago, natural predators, such as wolves and cougars, no longer live in northeastern Illinois.

At the same time, suitable habitat for deer dwindles. In the 1970s, urban development accelerates in DuPage County, and open spaces quickly become subdivisions, strip malls and roads. By the end of the century, only a few thousand acres of protected land remain for the burgeoning populations of deer.

What's the problem?

Unnaturally high concentrations of deer — far more individuals per square mile than the land can support while still maintaining significant biodiversity — affect a vital link in a forest preserve's food chain: plants. Many plant species cannot rebound after unusually heavy foraging. The decrease in diverse, edible vegetation affects wildlife along the entire chain.

Some deer, wandering into neighborhood yards for vegetation, damage costly landscaping in the process. High deer densities also trigger an increase in deer-vehicle collisions and — due in part to poor diet and frequent animal-to-animal contact — the deer's susceptibility to disease.

What's the answer?

After much consideration, District ecologists came to the conclusion that deer populations needed to be managed to protect the county's biodiversity. Ecologists evaluated several removal methods on the basis of effectiveness, practicality, and humane treatment and came to the difficult conclusion that lethal removal was the best solution.

The District's decision was not unique. Other municipalities and natural resource agencies throughout the United States and Canada have reached the same conclusion. The District's deer-removal program is implemented in accordance with IDNR regulations and has received the endorsement of 27 environmental and conservation organizations, including a local animal-welfare group.

Can't the District relocate or sterilize the deer?

Unfortunately, no. Studies show that the stress-related effects of capturing, handling and transporting deer increase deer mortality, even with precautions to minimize stressors. More importantly, other areas of the state - and country - have their own deer dilemmas; if deer in DuPage County were readied for relocation, there would be nowhere to take them. And while researchers have tried to develop chemical means to prevent deer from reproducing, to date, there have not been any practical successes.

How does the deer-management program work?

In its 16th year, the program operates in late fall and winter under stringent safety guidelines. The District posts warning signs at major forest preserve access points and sends letters to nearby residents.

All activity takes place at night, when the forest preserves are closed, in safe zones carefully previewed and designated by the Forest Preserve District and the IDNR. Only District or U.S. Department of Agriculture employees participate. All shots are taken from elevated positions by sharpshooters who have successfully completed IDNR certification and are approved by multiple team members to ensure ballistics remain within the safe zone. The program avoids areas closest to roads and residences, but neighbors may still hear isolated gunfire originating from within the preserve or see District vehicles, lights or related activities.

The meat is inspected, processed at a licensed facility and donated to area food pantries; last year, the District donated over 12,000 pounds of venison.

How does the District decide where to remove deer?

Each winter, District ecologists conduct aerial surveys to estimate the number of deer in the forest preserves. During the spring and summer, they study plant communities and document the extent of deer browse, especially on rare or protected plants and plant communities. If a loss of diversity can be attributed to high deer densities, ecologists may determine deer-removal efforts are necessary.

Does the program work?

When the deer-management program started in 1992, deer had consumed much of the vegetation within their reach in several forest preserves. Ecologists established small, experimental plots at these preserves and installed fences to prevent deer from reaching the vegetation inside each plot. Inside the fenced areas, vegetation grew thick; outside, the deer grazed plants down to the ground. Today, plant growth inside and outside the fenced areas is similar, several species have begun to recover, and the forest preserves have moved toward becoming biologically diverse ecosystems once more.

How many years will the program run?

The program has had successes, but work still remains. In some forest preserves, populations have not yet been reduced to numbers that promote biologically diverse areas. Other forest preserves have reached this point, but populations still need to be maintained to keep ecosystems in balance. The deer-management program will likely be a long-term necessity to ensure the health of DuPage County's natural areas.

What if I have more questions?

For questions regarding the IDNR's urban deer project, call (847) 798-7620. For further information on the Forest Preserve District of DuPage County's deer-management program, contact the District's Office of Public Affairs at (630) 871-6406.