Mammals

Bats

The Forest Preserve District conducts bat surveys in late summer to determine the distribution of species in DuPage County. To date, efforts have documented red, little brown, northern long-eared, silver-haired, hoary and big brown bats.

Coyotes

Description

Coyotes are yellowish gray with bushy black-tipped tails and whitish throats and bellies. They are 23 to 26 inches high and 3 to 4.5 feet long and typically weigh 25 to 35 pounds. They look similar to small German shepherds.

People frequently report seeing 80-pound coyotes, but data does not suggest they reach this size in the Chicagoland area. Because coyotes have long legs, are tall for their size and possess long, thick, furry coats, they may seem larger than they actually are.

Coyotes are often mistaken for wolves but are smaller and more slender with narrower snouts and more prominent ears. They run with their tails hanging lower below the back; dogs and foxes usually run with their tails sticking straight out.

Tracks

Coyote tracks are roughly 2.5 inches long by 1.25 inches wide. They tend to be more oval-shaped and compact than domestic dog tracks, which are more circular. All four toes on a coyote’s foot leave an impression; the nail marks are less prominent, but the top two nails typically leave marks.

Coyote tracks tend to follow a straight line; dog tracks tend to meander, just as a dog meanders to investigate smells and sounds.

Scat

Coyote scat, which is about as wide as a cigar, contains signs of the animals’ diet, such as hairs, feathers, seeds and grasses. Coyotes drop their scat in conspicuous locations to mark their territories, including developed trails and footpaths.

Food

Over 90 percent of a coyote’s diet is small mammals, such as squirrels, voles, mice and cottontails; but it is an opportunistic hunter that feeds on what is available, including birds, snakes, insects, fish, fruits, vegetables, injured or sick deer, or fresh carcasses.

Habitat

Coyotes are adaptable and live in nearly every type of habitat, including woodlands, prairies and suburban neighborhoods, although they prefer more open areas, such as grasslands, with abundant prey.

Behavior

Coyotes travel along trails, paths, ridges and waterways and are typically nocturnal. They are most active between dusk and early morning but may be active during the day, especially in winter when food is scarce and daytime foraging is necessary.

Coyotes are either nomadic or territorial. In northeastern Illinois, individual nomadic coyotes can drift over 20 square miles.

Territorial coyotes stake out their territories, find mates and breed. One family group in northeastern Illinois may occupy about 3 square miles. Territorial coyotes sometimes hunt in family units called packs as they teach their young how to forage and work together to corner nimble prey, but individuals or male-female pairs are more common.

Communication

Coyotes communicate using body language, odors — from glands, urine or feces — and vocalizations. They use threatening barks when guarding a den or a fresh kill and howl to announce territories. (Contrary to popular belief, they do not howl to announce a successful kill.) Yips announce playful celebrations or criticism, and huffs call young without drawing attention.

Barks and yips increase in power and pitch and end in long, flat howls that can carry 2 or 3 miles. Howls increase during mating season and decrease when the animals have their young. They are known to howl in response to train horns, emergency vehicle sirens and other high pitched sounds. Their diverse vocalizations can make two or three individuals sound like six or more.

Reproduction

Coyotes usually have one litter per year. The mating season peaks in late February or early March. Gestation is approximately 58 to 65 days; pups are born in late April or May. Litters of two to 19 pups have been recorded but six to seven pups per litter is average. Only 5 to 20 percent of pups survive their first year.

Den sites may be underground; under hollow trees, logs or brush piles; or in abandoned buildings but most are in vacant fox or woodchuck burrows. Pups are born blind and stay in the den with their mother for the first three weeks. In spring and early summer, parents are busy trying to find food to feed their pups. The pups begin to hunt on their own when they are two to three months old and are on their own at six to nine months. Young, inexperienced coyotes start to establish their own territories and find mates during two main periods, in fall or late winter.
Some people believe that coyote populations are increasing, but there is no data to support this. The perception is likely a result of a number of factors. First, urban development continues to move people into existing coyote territories. As a result, coyotes are slowly getting used to human activity. They are less likely to shy away from humans and more likely to be seen. Second, suburban landscapes typically have more sources of food than natural settings and can support slightly higher densities. Third, it is likely that more people are merely seeing many of the same coyotes.

Some also believe that coydogs — a coyote and domestic dog mix — are common, but genes from domestic dogs have rarely been found in a coyote’s genetic makeup. Coyotes and dogs are capable of producing hybrid litters, but the chance of successful pairings is low. Coyotes are seasonal breeders; dogs are not. And because neither dog nor coydog males help care for their pups, coydog pup survival rates are low.

Longevity and Mortality

In rural areas, coyotes typically live to be 3 or 4 years old. In suburban areas, many live to only 2 years of age, although a few may live to be 12 or older. In Illinois, natural predators like wolves or cougars no longer exist, but other forces influence coyotes’ longevity. In one suburban study, 70 percent of tracked coyotes were killed by vehicles.

Ecosystem Role

In urban and suburban areas, coyotes are often the top predators, which provide a significant service by maintaining ecological balance. Without coyotes as a control, populations of other species, such as eastern cottontails or small rodents, would explode and start to negatively affect the area’s ecological balance. Coyotes help to regulate populations of several species, accounting for 20 to 70 percent of deer fawn and 40 percent of Canada goose nests each year.

Learn about how to live with urban coyotes. View the video Being Coyote Wise: Living with Urban Coyotes.

White-Tailed Deer

Perhaps the most recognizable animal in DuPage County, the white-tailed deer needs little introduction. White-tailed deer are herbivores that eat both woody vegetation, like trees and shrubs, and herbaceous vegetation, like wildflowers and grasses. They can breed at a young age, and many produce more than one offspring a year, every year. Adult females will usually have twins, but when nutritious food is plentiful, triplets or even quadruplets are possible.

White-Tailed Deer and Ecosystem Management

For thousands of years, humans had little effect on the region’s population of white-tailed deer. In the 1800s, though, an influx of settlers from the eastern United States began to replace forests with lumber yards and prairies and wetlands with farms. By the second half of the 20th century DuPage County farms were offering a convenient, abundant source of nutritious food, and white-tailed deer populations multiplied annually; without natural predators, they did so unchecked. As accelerated development converted open land into subdivisions, strip malls, and roads, only a few thousand protected acres remained for DuPage County wildlife.

Because of this complex chain of events, parts of DuPage County are now experiencing unnaturally high concentrations of deer — far more individuals per square mile than the land can support while maintaining significant biodiversity. This has led to increases in deer-vehicle collisions, damage to private landscaping, foraging of sensitive forest preserve plant communities, and animal-to-animal contact, which dramatically increases susceptibility to disease.

The Decision to Manage Deer Populations

After much consideration, Forest Preserve District ecologists came to the conclusion that the county needed a deer-management program to protect the area’s biodiversity. They 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 option. Numerous agencies throughout the United States and Canada have reached the same conclusion, and the District’s program has received endorsements from 27 environmental and conservation organizations, including a local animal-welfare group.

Problems With Relocation and Sterilization

Studies have shown that the stress-related effects of capturing, handling and transporting deer increase mortality, even with precautions to minimize stressors. More importantly, other areas of the state and country have their own deer dilemmas: If the Forest Preserve District did capture deer 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.

Elements of the Deer-Management Program

Each winter, Forest Preserve 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 they can attribute a loss of diversity to high deer densities, they may determine deer-removal efforts are necessary at a given forest preserve.

The District’s deer-management 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 designated safe zones that the Forest Preserve District and the Illinois Department of Natural Resources carefully select and preview. Only District and U.S. Department of Agriculture employees participate. All shots are taken by IDNR-certified sharpshooters from elevated positions, which multiple team members approve in order 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 and processed at a licensed facility and donated to area food pantries. On average, the District donates over 15,000 pounds of ground venison each year.

Results

When the deer-management program started in 1993, 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 fenced areas are similar, several species have started to recover, and forest preserves are once more becoming diverse ecosystems.

The Program’s Future

The Forest Preserve District’s deer-management program has had successes, but work remains. At some forest preserves, populations are still too dense to promote biodiversity. At others, populations have stabilized but require maintenance to keep ecosystems in balance. Without natural predators to keep populations in check, the deer-management program will likely be a long-term necessity to ensure the health of DuPage County’s natural areas.