Ball cactus is a state listed endangered plant and is found on the granite rock outcrops on the refuge. This is a warm season cactus that flowers in June and July and produces fruits in the fall. Visitors to the refuge may encounter this cactus along the Rock Outcrop Trail accessible from the auto tour route. Other cactus that may be encountered along this trail and the granite outcrop habitat is the brittle prickly pear.
 

After the cold, windswept days of winter have ended and warmer temperatures gradually replace them, visitors to the refuge are delighted with a look to the sky for migratory birds to arrive. In the tallgrass prairie habitat the bobolink is a must see bird species. Bobolinks arrive in mid spring and nest in dense cover of forbs. This species is seen frequently along the auto tour route in the grassland habitats and along wetland edges. When driving, listen for the male’s loud, bubbly bob-o-link song.
 

During the summer months, visitors are likely to see numerous flashes of yellow. Those flashes are an indication that breeding yellow warblers and goldfinches have returned. Look for these brilliantly colored birds in riverine habitat and along forest edges.
 

Big Stone National Wildlife Refuge historically offered a combination of small wetlands and abundant prairie that was critical to waterfowl breeding and nesting. Small wetlands – some temporary and some permanent, provided not only nesting habitat, but food and shelter for egrets, herons, and other waterbirds. The Highway 75 dam created two impoundments (West and East Pools), that added additional 4,250 acres of wetlands to the refuge. Water levels in these two pools can be managed to provide the right mix of plants and waters during different seasons. Refuge wetlands support a diversity of wildlife by providing resting, feeding, and nesting for birds, but also look for snapping turtles, western tiger salamanders, frogs, and toads in these habitat types. Along the banks and edges of these habitats you can also find mink, river otter, and ground squirrels.

The abundant grasslands that once covered west central Minnesota were critical for nesting waterfowl and a variety of other birds. This is typical tallgrass prairie country where only occasional oak trees can be found.The refuge is fortunate to have 1,700 acres of remnant or unplowed prairie. Remnant Tallgrass prairie once covered more than 25 million acres of Minnesota and Iowa. The original Tallgrass prairie is mostly gone now with only one-tenth of one percent remaining.
 

Big Stone National Wildlife Refuge is named for the 100 acres of granite outcrops. These bare rock areas support unusual species of endangered cactus including the ball cactus. Some of these rock outcrops are very large and offer amazing panoramic views of the entire refuge and its wide variety of wildlife. Species that use this habitat the most are skinks, common nighthawks, and snakes.