May 2, 2022
Photo by Kathy Andrews Wright.

A Spotlight Survey Ride-along

By Kathy Andrews Wright

The email started with an apology for the late notice but explained that the weather forecast called for ideal conditions to conduct the annual Sangamon County furbearer spotlight survey the following evening. 

A adult male white-tailed deer with large antlers stands in a grassy area silhouetted at dusk against a lavender sunset.
Photo by N. & M. J. Mishler, USFWS.

“Would you be available to meet us about 8 p.m.,” Stan McTaggart, Illinois Department of Natural Resources (IDNR) Furbearer Program Manager inquired.

A variety of factors played into the decision to GO. The evening’s temperature would be above freezing, the humidity was predicted to be above 60 percent and winds would be less than 10 mph. All three criteria would maximize wildlife activity.

Starting the route one hour after sunset, ours was a slow and circuitous route winding through the countryside at 10 to 15 mph. Spotlights illuminated both sides of the roadway, one operated by McTaggart and the other by Pat McDonald, Wildlife Biometrician for the IDNR Forest Wildlife Program.

The 100,000-candelpower spotlight beams swept back and forth across open fields, up and down the trees, across ditches and down streams.

“You see the first layer of shrubs along the road” McTaggart asked. “We have a 10- to 14-day span of time in the spring to conduct these surveys before the leaves emerge on woody vegetation. One of the earliest species to leaf out is that shrub—the exotic, invasive bush honeysuckle. By the time its leaves are the size of a quarter it is difficult to see animals with a spotlight.”

A graphic that includes a photo of a black, gray, and white raccoon resting on a tree branch. Below the raccoon and overlayed on the photo is a chart showing the number of raccoons observed per mile during Illinois furbearer spotlight surveys.

Along the first mile the biologists called out the species sighted.

“Raccoon. Another raccoon. Five deer. Another five deer. And five more deer.”

Often the first indication of the presence of an animal is the eyeshine, or the reflected light, and whether it is red, green, gold or green. Biologists must then quickly assess the shape of the animal, height off the ground, mode of movement and how the animal reacts to the light.

As we encountered, it isn’t surprising to have local landowners—citizens stewarding the resources—pull up alongside the survey vehicle, inquiring about the activity under way. The local sheriff’s department had been notified in an advance of the survey in case other landowners called in to report the spotlighting activity. In many instances, an IDNR Conservation Police Officer rides along, scanning one side of the road while a wildlife biologist works the other side.

Mile by mile, minute by minute, the drive continued, and the list grew.

“A striped skunk. One rabbit. Three deer.”

Respectful of homeowners, beams are lowered while passing homesites and observers are careful not to spook livestock.

In existence since 1981 and conducted each year, save for 2020 due to COVID-19 restrictions, the purpose of the surveys is to inventory the number of target species—raccoons, deer, rabbits, opossums, skunks and feral cats—observed every year, driving the same routes across the state. But records are made of other species noted, such as coyotes, American badgers, bobcats, minks, river otters, cows, geese and barred owls. As well the elusive sighting simply noted as “unknown,” which are, most likely, coyotes, foxes or bobcats that are suspicious of slow-moving vehicles and do not stick around long.

A domestic black cat sitting in a grassy area at night time. Its eyes are shining in the spot light.
Photo by Karan A. Rawlins, University of Georgia,

“The spotlight survey is one of several tools that biologists have for obtaining an overview of trends for the state of Illinois’ furbearers,” McTaggart explained. Other annual surveys include roadkill, hunter harvest and trapper harvest surveys. While these surveys have different approaches, the results generally show similar trends over time.

A single year of data provides a snapshot of wildlife at one point of time that can be influenced by factors including variations in weather and environmental conditions. For biologists, value exists in the long-term data set that provides information on trends. Comparing trends collected from the 40 to 45 standardized routes driven each year for more than 40 years allows the IDNR to make critical, informed wildlife management decisions.

One example of how the spotlight survey data has been used is the adjustments made to the length of the raccoon hunting and trapping seasons. As noted in the Illinois Spotlight Surveys, in 1981 one raccoon was sighted for every 2 miles driven. The number of raccoons has steadily increased over 40 years, with almost two raccoons noted per mile driven in 2021.

“While the raccoon population has increased across the state, the number of people harvesting animals was in decline, from upwards of 21,000 licensed trappers in 1979 to approximately 7,000 today,” said McTaggart. This decline in participation is generally linked to a weak fur market and low prices for raccoon pelts.

A gray and brown coyote stands in a woodland area at  night. Leaf litter covers the ground.
Photo by Rick Roseman,

“As a result of the survey data showing increased abundance of many species and interest from trapping groups such as the Illinois Trappers Association, the hunting and trapping seasons for furbearers have been extended since the 1980s. This not only allows more time in the field for hunters and trappers to pursue raccoons and other furbearers, but also provides more opportunity to control a species that can cause property damage when they get into attics, garages, boats, etc.”

In Sangamon County, the miles continued to roll by until the 25-mile route was completed at 11:34 p.m. The evening’s tally included 50 raccoons, 347 deer, 11 rabbits, 4 cats, 8 opossums and 3 skunks. The tally sheet also noted one “unknown” mammal—most likely a coyote or red fox—and that the Sangamon River was flooded, which likely contributed to deer moving out of the bottomlands to the higher ground where they were sighted.

This snapshot of a moment in time in central Illinois, along with the records of the nearly 1,000 miles covered elsewhere during the 2022 spotlight surveys, will serve for years in the continued understanding of Illinois’ furbearer populations.

Additional Reading

Comparing and Contrasting Trends in Harvest and Non-Harvest Based Indices of Furbearer Abundance 

An Approach for Using Multiple Indices for Monitoring Long‑term Trends of Mesopredators at Broad Spatial Scales

Kathy Andrews Wright is retired from the Illinois Department of Natural Resources where she was editor of Outdoor Illinois magazine. She is currently the editor of Outdoor Illinois Wildlife Journal and Illinois Audubon magazine.