Kohler-Andrae State Parks Discovery Bird Walks. Ages 8 and older. Master Naturalists Janet & Andy Raddatz will lead the Discovery Bird Walk. Meet at the Black River Trail parking lot to observe birds and nature in the park for about 2 hours. Portions of the trail may be wet or muddy, so wear appropriate shoes or boots and dress for the weather. Bring insect repellent, sunscreen and binoculars. The 1.5 mile walk is best for ages 8 and older; children must be accompanied by an adult. Please, no dogs on the walk. All vehicles need a state park admission sticker.