The 10,645-acre Horseshoe Lake Conservation Area, featuring 2,400-acre Horseshoe Lake, is located near the town of Olive Branch in extreme southern Illinois. This region is reminiscent of Louisiana with its swamps dominated by bald cypress and tupelo.
John James Audubon traversed the region close to this state wildlife area, and many noted Illinois ornithologists, past and present, have used the area as a study site. The state purchased the first parcel of land here in 1927. Today, the property contains two state-dedicated nature preserves, which harbor a near-virgin forest of beeches, sugar maples, swamp chestnut oaks and American elms. This forested land was designated a National Natural Historic Landmark in 1974.
With its 30 miles of shoreline and 2,400 acres of open water, Horseshe Lake Conservation Area provides a migratory and wintering haven for thousands of ducks and geese and dozens of Bald Eagle, as well as an occasional Golden Eagle that feed on the waterfowl.
In summer, breeders include Northern Parula, Louisiana Waterthrush, Ovenbird, and Kentucky, Hooded, Yellow-throated and Prothonotary Warblers. Red-shouldered Hawk, Broad-winged Hawk, Barred Owl, Pileated Woodpecker, Mississippi Kite, Whip-poor-will, Chuck-will's-widow, Wood Thrush, and occasionally, Brown Creeper nest within the preserve's boundaries as well.
Various herons breed and/or forage in the flooded fields and bottomland forest. Species include Little Blue Heron, Yellow-crowned Night-Heron, Great Egret, Cattle Egret and Snowy Egret.
This site was chosen as an IBA because it met the criteria for breeding Brown Creeper, winter Rusty Blackbird congregations, and Waterfowl.