The 1226-acre forest preserve is part of a larger 1700-acre complex of forest preserve lands along Mill Creek, Fourth Lake and Third Lake in Lake County, Illinois. Rollins Savanna contains oak savanna, basin marshes, riparian marshes, wet/mesic/dry prairie, low gradient stream, and approximately 600 acres of former agricultural lands. Large scale prairie, savanna and wetland restoration is ongoing. Field tiles have been disabled, all agricultural lands have been seeded to cover crop and are being seeded in with prairie species. Wetland plugs are also being planted.
The grasslands, hemi-marsh wetlands and scattered savannas of this forest preserve provide copious breeding opportunities for wetland and grassland species, whose numbers are declining nationwide. Careful management of this relatively new forest preserve can help maintain a reliable spot for these birds to come each summer to raise young.
An extensive breeding bird survey done in 2007 at Rollins Savanna produced 15 pairs of Yellow-headed Blackbird, 4 pairs of Common Moorhen, 3 pairs of Least Bittern, 3 pairs of Sandhill Cranes, at least 1 pair of King Rail and 1 of American Bittern -- all species of conservation concern.
The site also provides breeding habitat for more common wetland species such as Sora, American Coot and Mallard. Less common breeding species counted in 2007 include Wood Duck, Ruddy Duck, Gadwall, Virginia Rail, Spotted Sandpiper and Marsh Wren.
Wilson's Snipe may also be nesting at this preserve.
The 2007 survey also indicated grassland species are doing very well at the preserve. At least 14 pairs of Henslow's Sparrow, 23 pairs of Bobolink, 25 pairs of Eastern Meadowlark, 29 pairs of Savanna Sparrow and 28 pairs of Sedge Wren used the preserve for breeding. Seven pairs of Blue-winged Teal also used the grasslands for breeding.
Scattered shrublands supported 9 pairs of Willow Flycatcher and 5 pairs of Orchard Oriole in 2007 as well, along with much more abundant numbers of Common Yellowthroat.
In addition, wintering Short-eared Owl, Northern Shrike and Northern Harrier use the preserve during migration and winter, relying on the vole population and grasslands for hunting.
This site was chosen as an IBA because it met the criteria for breeding Yellow-headed Blackbird, Henslow's Sparrow, and Common Moorhen.
Threats include invasive species and water quality/ altered hydrology. Human recreation will be carefully monitored and managed to the extent possible - e.g. off-trail use of snowmobiles or dogs off-leash could disturb grassland nesting as well as wintering species. Trails were located at habitat edges to reduce fragmentation and edge-effect. A viewing platform is being erected to encourage birders to stay on the trails.