A Haven for Grassland Birds and More

During a meeting at the Joliet Army Ammunition Plant back in 1982, biologists with the Illinois Department of Natural Resources noticed something incredible. High up on utility poles on the manufacturing (west) side of the Illinois Route 66 Scenic Byway, they spotted a species of grassland bird that had been scarce in the area for quite a long time: upland sandpipers. Populations of “u-sands,” as grassland bird enthusiasts affectionately call them, were thought to have long diminished from the area.

Inspired and filled with hope for the future of the arsenal site as a potential haven for upland sandpipers and more, grassland bird experts organized surveys to try to get an idea of just how many upland sandpipers were on the arsenal. Surveys in 1983 and 1984 showed the largest population of u-sands in the State of Illinois. 

Surveyors noticed most of the u-sands were nesting in the livestock grazing tracts.

In 1985, surveys were expanded to cover grazing and hay fields, approximately 5,000 acres, to look for all grassland birds. It soon became clear that the ammunition plant was one of the most important grassland bird areas in the state, perhaps in all of the Midwest. 

More recently, over 25 years since Midewin NTP was established in 1996, spottings of native Illinois grassland birds – and rare birds of all kinds – continue to increase.

Midewin NTP staff and volunteers conduct annual bird surveys at Midewin NTP with the Illinois Department of Natural Resources; The Nature Conservancy in Illinois; and the Illinois Audubon Society.

Illinois Audubon Society Executive Director Dr. James Herkert said that numbers of dickcissels and Henslow’s sparrows have been increasing in recent years. Numbers of bobolinks and grasshopper sparrows have remained stable, even though their numbers have not been as steady elsewhere. He credits the bird-friendly habitats for why the birds are returning year after year. 

“Midewin offers both a lot of habitat and a wide variety of habitat,” Herkert said. “Recent observations really point to Midewin being a very important area for grassland birds.”

Bird monitors are seeing some species for the first time ever. Recent annual bird surveys point to increases in some grassland bird species while numbers of other species are steadier here than elsewhere.  

In June 2019, at Turtle Pond, on the northeast side of the Illinois Route 66 Scenic Byway, a tropical-looking painted bunting rested for at least two weeks before continuing on through its migration further north. Pairs of sandhill cranes, a black-necked stilt, bald eagles and more have been spotted thriving.   

With their in-flight battles over voles on the ground in the southeast bison pasture, short-eared owls and northern harriers amaze and delight photographers from everywhere in the late afternoon/early evening hours just before the sun sets.

 

Different species of birds prefer to live in different lengths of grasses. Volunteers, partners and staff are working to ensure that short, medium and tall grasses are maintained as suitable habitat that can attract and support all grassland birds.

The most critical grass habitat at Midewin is short-stature grasslands.

Cattles help to provide short-stature grass habitat with their grazing. Mid-stature grass habitat is increased where hay is mowed and where pastures are idle. Prairie reconstructions and other non-grazed areas provide tall grass habitat.

The lands at Midewin NTP have a long history of cattle grazing, especially the area west of the Illinois Route 66 Scenic Byway. In much of that area, plowing for crops was not feasible because the dolomite limestone is so close to or even at the surface. Instead, the farmers used the area for pasture, and that practice was continued on buffer lands while the U.S. Army administered the Joliet Army Ammunition Plant. 

Grass height is monitored during late spring and early summer to determine if the proper habitat structure is being maintained. Tallgrassareas don’t differ much from year to year, so medium and short grasses are given priority.  

The Robel pole method is used to determine grass height.

Grazing tracts are measured more than non-grazing tracts to help determine the proper number of cattle needed to achieve the desired results.

Some crop fields have been converted to grazing tracts and brush has been cleared from existing grazing tracts. 

The loggerhead shrike and other grassland birds While some grassland birds require wide-open areas with few to no shrubs. the Loggerhead Shrike prefers short-stature grassland with some shrubs for nesting. Many of the loggerhead shrike nests that are found are located in shrubby trees along the edges of unfragmented tracts. The shrubby trees are left there during brush cutting work days because loggerhead shrikes like to nest in them.

 

Midewin NTP provides one of the last opportunities in this region to create relatively large grasslands for several threatened birds, including Bobolink and Loggerhead Shrike.