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OUR NATURAL RESOURCES

BY ANNE MUELLER 

It was the grasslands, of course, that gave the Prairie State its name, a name that today seems something of a misnomer. A Natural Areas Inventory completed 20 years ago found only 2,352 acres—just 1/100th of 1 percent—of high-quality original prairie remaining.

With the loss of the prairie came the decline of wildlife that depended on its habitat. Among the casualties were grassland birds, which had fewer insects and fewer seeds to eat and less ground cover for nest building and survival. With their decline, a part of Illinois' natural heritage, inherited in near pristine form in 1820, was diminished.

Three studies being underwritten this year by the Illinois Wildlife Preservation Fund will gather data to help restore a part of that heritage dealing with grassland birds: a $16,000 project will use satellite imagery to identify the largest blocks of grasslands that currently exist in Illinois, with an eye toward managing some large areas to benefit grassland bird species; a $14,000 project will study grassland birds at the Savanna Army Depot in northwestern Illinois; and a $ 10,000 project will monitor birds at Green River State Wildlife Area in Lee County.

Grassland birds, along with wetland/aquatic, scrub/ early successional, woodland and urban birds, comprise the categories of breeding birds found in Illinois, Grassland species eat the insects, cutworms, seeds and grains that grasslands, including pastures and open fields, provide. Most nest on or near the ground, while a few species build nests on low brush or in scattered trees.

Included among grassland birds are eastern meadowlarks, bobolinks, dickcissels, northern harriers, sedge wrens, short-eared owls and barn owls, plus a variety of sparrows—savanna, field, grasshopper, lark, vesper and Henslow's. Some species, like the Henslow's sparrow, short-eared owl and northern harrier, are classified as endangered on the Illinois Checklist of Endangered and Threatened Species. Others, such as the Eastern meadowlark, have adapted to the pastures, hayfields and row crops that replaced Illinois' original prairie landscape.

Jim Herkert, project manager for the Endangered Species Protection Board, has conducted research during the last decade that shows grassland bird guilds are declining in greater proportion than other types of birds, although wetland species have undergone the worst decline in pure numbers. Appearing to play a big role is habitat fragmentation, in which large expanses of contiguous landscape are broken up either by another type landscape or by structures, roadways or other encroachments.

"We found, as had previously been determined for woodland birds, that grassland bird numbers are low in fragmented habitat areas," Herkert said. "We now know that grassland birds need large expanses of grassland habitat to be abundant. In addition, there's increasing

46 / Illinois Parks and Recreation

For example, he said research conducted at the new Midewin National Tallgrass Prairie near Joliet shows that the short grass of pastureland provides excellent brooding habitat for upland sandpipers, a grassland bird species that's endangered in Illinois. Herkert says pastures have been critical to Midewin (pronounced Mid-DAY-win) supporting large numbers of sandpipers.

"Some might be surprised to hear us say we need the cows there,'" Herkert said. "But if we took out the pastureland, I firmly believe we'd lose the majority of upland sandpipers at Midewin."

The satellite imagery project financed by the Wildlife Preservation Fund will identify places in Illinois that contain a high proportion of grass in relation to shrubs and trees. The satellite images will be overlaid with soil maps to identify areas that used to be prairies. Herkert notes any potential restoration efforts likely would be more successful if they were attempted on former prairie land.

The project would first look for state sites where grassland management could be implemented on a large or "landscape" scale. Data collected by the project also would be used to identify private land holdings where incentives might be proposed to landowners to keep their lands in pasture.

The Savanna Army Depot project will take a different approach to increasing grassland bird numbers. Like Midewin, where the Defense Department formerly operated the Joliet Army Ammunition Plant, the Savanna Army Depot is scheduled for closure and undergoing review by a local reuse authority. Among the options the local group is considering is transferring some of the depot's 13,000 acres to conservation interests.

Money from the Wildlife Preservation Fund will be used to support a summer field crew of nest searchers at the depot. They will gather baseline data on grassland bird abundance and nest success to help in designing conservation strategies. Their work also will tell us more about grassland birds that use sand prai-

March/April 1997 / 47 

OUR NATURAL RESOURCES

ries and sand savannas, which comprise 5,500 acres of the site. 

In another technique suited to fields with shrubs that would snag a rope, crew members walk parallel a few feet away from each other and watch for birds being flushed. As with the rope dragging technique, birds and their eggs are not injured, and the birds return to their nests after the searchers leave the area.

A third technique is observation. If a male is heard singing or if birds are seen repeatedly returning to the same spot with nesting materials or food for their young, it's indicative of a nest. Whatever procedure is used, Herkert says the nest-searching process is tedious.

"Nests for grassland birds are really, really hard to find," he stressed.

Despite the difficulty in finding them, it's important that searchers find large numbers of nests so adequate information can be obtained and compared year to year. Herkert says that two years' worth of data for grassland and shrub species include information from about 1,400 nests, a number that Herkert would like to see increased.

Once a grassland bird's nest is found, colored stakes are placed a given distance from it and bearings are taken using identifiable landmarks. This "remote" identifying technique is preferable to pounding a stake into the ground right next to a nest, which would disturb the incubating bird and the nest's contents.

In order to gather information about the nests, including reproductive success and predation, the nests are monitored every three days. Visiting the nest more often likely would result in excessive disturbance, Herkert said, while monitoring less frequently would yield inadequate information. At each visit, field crew members record the contents of the nest, the presence of an adult bird and the birds' behaviors. If a nest is empty, searchers record whether the young have fledged or if predators have disturbed the nest.

Herkert says nest predation rates are high for grassland species, whose ground nests are readily accessible to snakes, skunks, opossums, raccoons and ground squirrels, as well as crows and blue jays.

"No one predator is the problem. Its their cumulative impact," Herkert said. "Everything will be fine one day, and the next time you check a nest, it will all be gone."

An infamous brood/nest parasite that Herkert isn't too concerned about is the brown-headed cowbird, which lays its eggs in other birds' nests, deposing the original occupants which, when they hatch, often die from parental neglect. It's well documented that woodland bird species, affected by habitat fragmentation that allows cowbirds easier access to forest interiors, have suffered population declines due to cowbird parasitism.

However, Herkert says cowbird parasitism rates for grassland bird species are low enough that he considers it a minor issue. Any cowbird eggs that nest searchers encounter during monitoring activities are left as they're found so as to not influence data.

Because woody encroachment into grasslands is known to significantly elevate predation rates and otherwise adversely affect grassland species, the Green River State Wildlife Area project will look at how an aggressive woody species management program is benefiting grassland birds. The project also will compare such management practices as mowing, woody removal and prescribed burning for restoring the area to its original grassland habitat.

Herkert says prescribed burns, primarily conducted in the spring, affect grassland birds differently. Bird populations for Henslow's sparrows and sedge wrens, for example, first drop and then rebound after a burn. Other species, including grasshopper sparrows, see their numbers go up immediately. For other species, such as bobolinks, the seasonal spring timing of a burn can either positively or negatively affect bird numbers.

Herkert says that the results of earlier research will come into play as management techniques are implemented.

"We know we need a mosaic of recently burned areas interspersed with areas that aren't burned to provide a full range of habitat," Herkert said.

Individuals can add to the body of knowledge about Illinois wildlife and its habitats by supporting the Wildlife Preservation Fund, Tax deductible contributions can be made by indicating an amount on Line 15a when filing regular state income tax forms. Line 7a of the EZ form or Line 11a of the Telefile form. Throughout the year, donations can be sent to the Wildlife Preservation Fund in care of the Department of Natural Resources, Division of Natural Heritage, 524 S. Second St., Springfield, 111. 62701-1787. 

ANNE MUELLER
is a staff writer for OutdoorIllinois, a publication of the Illinois Department of Natural Resources. Reprinted from the February 1997 OutdoorIllinois.

48 / Illinois Parks and Recreation

"With more than 90 percent of Illinois' land privately owned, it is critical for government to work with private landowners to protect our environment," the Governor said. "I'm proud this program is helping shape Illinois' landscape for future generations and serves as a national model for environmental management."

The partnerships receiving grants have donated nearly $2.3 million of their own to the projects, either through cash or in-kind contributions. Grant funding comes from Conservation 2000, the Governors comprehensive six-year initiative to protect Illinois' natural resources.

The program provides financial and technical assistance to landowners interested in maintaining and enhancing both ecological and economic conditions in key watersheds throughout the state. The program includes habitat restoration, enhancement and protection projects, as well as funding for education, research and planning.

In addition to the project grants listed below, the Kankakee River, Carlyle Lake and Peoria River Bluffs ecosystem partnerships each will receive $10,000 in one-time assistance to complete watershed plans.

Grant recipients include: Big Rivers Ecosystem Partnership; Cache River Partnership; Chicago Wilderness Partnership; Embarras River Partnership; Fox River Partnership; Headwaters Partnership; Kaskaskia River Partnership; Kishwaukee River Partnership; Mackinaw River Partnership; Prairie Parklands Partnership; Rock River Partnership; Upper Des Plaines Partnership. 

Using cutting-edge satellite technology, DNR has produced a comprehensive atlas of Illinois land cover, a wall map and a CD-ROM. These materials are the second phase of the Critical Trends Assessment Program, an ongoing evaluation of ecological changes in Illinois' environment. The first phase, completed in 1994, provided an overall assessment of the condition of Illinois' natural resources.

The Land Cover Atlas is available as a bound, 300-page book. The full-color Land Cover Wall Map measures 30 inches wide by 54 inches long and includes information tables on 20 different types of land cover. The companion Land Cover CD- ROM will enable computer users to view the land cover images and conduct their own analyses of the information.

A more advanced 2 CD-ROM set is available for scientists, managers and planners who are Arclnfo or ArcView users and need more specific topography information. The Department also has published an inventory of 30 quot;resource rich" areas in Illinois which support, or have the potential to support, both area-sensitive and wide-ranging plant and animal species. The document is called "Inventory of Resource Rich area in Illinois: An Evaluation of Ecological Resources."

To order materials, some of which have a nominal fee to cover costs, contact Tracy Adamski, at 217.557.0483. 

March/April 1997 / 49