The many thousands of insect species requiring an underwater environment for their larval stage help sustain many species of terrestrial predators when the insects emerge from the water as adults. The kingfisher that nests here and the occasional great blue heron that stops during migration also enjoy the fruits of the water community, taking fish and frogs. But the process is not a one-way street. Nutrients leached from the land help fertilize the aquatic food chain. And the grasshopper that inadvertently hops into the river, only to disappear quickly into the gullet of a fish, represents another of the ongoing exchanges between land and water. As I round the sharp bend that sends the river flowing north again, a muskrat hurries into the water and submerges. On the steep bank high above the river, I wait until it surfaces in midstream. It floats lazily for a while, its long, naked tail straight with the slow current. Then it heads back toward shore. Across the river, the floodplain cottonwoods bear the scars of beaver teeth. Some are girdled and dead. Others are in full leaf despite deep but incomplete incisions. Growing dusk fills the river valley. In the failing sunlight vanquished to a thin, vertical display on the Tower face, it is almost possible to imagine what this splendid landscape must have been like as wilderness. Bison, not cattle, would have grazed nearby. Instead of the howling dog that has escaped the campground and races into the prairie dog town, a wolf might be pressing home its attack on an injured pronghorn. Grizzlies and cougars knew this valley, and the river was tamed not by a nearby reservoir but by a latticework of beaver dams. There are no prairie dogs left above ground now to challenge my trespass as I head back toward the welcome firelights of the campground. The deer have left their daybeds to graze in the open, and the great horned owl again asserts its dominance in the river timber. With a long rattle, briefly echoed from a cliff, the kingfisher quits the day. Beneath the expanding population of stars, I return to the comfort of hot coffee and the confines of my own world. For now, I am content with the memory of eagle and falcon. In my mind they will continue to soar, inspecting the splendid terrain my memory today acquired. Prairie Dogs: A Tight-Knit Society [Illustration: _A prairie dog family gathers at the entrance to their burrow, watching the activity in the town and keeping an eye out for intruders._] When the long grip of winter’s crusted snow relaxes, pasqueflowers burst forth in ravines, unplowed pastures, and abandoned cemeteries. Their delicate silvery purple contrasts with the bleak stubble of last year’s ruined grasses. Before plows ever broke the grassland sod, pasqueflowers were so profuse the distant ground seemed veiled in haze. The pioneers called it “prairie smoke.”