Our mission is to preserve, conserve, and restore biodiversity and biological integrity for the benefit of present and future generations of Americans. Big Oaks Refuge provides food and shelter for a wide variety of plant and animal species. More than 200 species of birds and 46 species of mammals are found on the refuge. Stream corridors and forested areas on Big Oaks Refuge provide excellent habitat for the federally-endangered Indiana bat, which uses the refuge for summer foraging, roosting, and for rearing young. The refuge also supports breeding populations of the river otter that were reestablished here in 1996. More than 500 pairs of state-endangered Henslow’s sparrows are estimated to breed in the large grasslands of Big Oaks Refuge. The refuge has been designated as a “Globally Important Bird Area” because of its value to Henslow’s sparrows and other migratory birds. Bald eagles and golden eagles are also known to use the refuge as a wintering site.