Important Bird Area.

Two endangered species are encountered a few times each year at Union Hills, Northern Harrier and Short-eared Owl. The High Conservation species American Bittern, Least Bittern, Black-crowned Night Heron, Forster's Tern and Black Tern, Grasshopper Sparrow and Bobolink have been recorded there each of the past three years. The grassland habitat has also been one of the few places in northern Iowa to hold Smith's Longspurs in migration. The complex of lakes and marshes is used by well over 1000 waterfowl in migration, and many remain to breed there.