 The Ohio River Valley might seem like an unlikely place for a national wildlife refuge. After all, wildlife refuges are often located in fairly pristine places, at a distance from human activities, not in the middle of one of America's most heavily commercialized river corridors. In the 18th and 19th centuries, the Ohio River was one of the most important avenues to the West, and explorers who traveled the river were struck not only by its beauty, but by the abundance and diversity of the Ohio River Valley's wildlife. Birds were so numerous that ornithologist John James Audubon, who lived along the river in the early 1800s, said it took only a few moments to capture a wild turkey or grouse to use as specimens for his drawings. Time passed, and the Ohio River developed into a major industrial corridor. Wildlife that had once seemed inexhaustible became increasingly scarce, or, in some cases, extinct. Part of the problem lay in the loss of habitat. The Ohio was a relatively shallow river, and beginning in the early 1900s, a series of locks and dams were installed along its length to allow dependable year-round navigation. But the rising water levels drowned dozens of islands. On many of the remaining islands, the forests were cleared for farming, oil and gas development, and eroded by sand and gravel dredging. Pollution struck another blow, as wastes from factories, mills and cities turned the Ohio's waters into a deadly stew. It was only after cleanup efforts took hold in the 1960s and 70s that biologists began to see the first glimmers of hope. Wildlife populations that had declined for decades were once again on their eyes. To help that resurgence, in 1990 Congress created the Ohio River Islands National Wildlife Refuge. Today, the refuge's many islands are scattered along 400 miles of the Upper Ohio River, from Pennsylvania to Kentucky. The waters surrounding the islands are home to more than 100 species of fish. The island's underwater areas also provide an important home for freshwater mussels. Many species of these unique creatures thrive on the river bottom, buried in the sand and gravel. Mussel populations were put under pressure in the first half of the 20th century, when their shells were harvested in huge numbers to make mother-of-pearl buttons. But perhaps the gravest threat to native mussels today is from a small, striped invader known as the zebra mussel. Zebra mussels attach themselves to hard surfaces, including native mussels, and can cause native mussels to starve by competing with them for food. Japanese knotweed is another species that is causing problems for wildlife. This fast-growing plant has taken root on the islands, crowding out native vegetation that animals need for food and shelter. The Ohio River Valley has historically been an important migratory corridor for birds, especially for the tiny songbirds that travel thousands of miles between wintering grounds in the tropics and breeding grounds in the north. While some of those species nest in a refuge, most use the refuge as a temporary stopover, resting in tree canopies. While migratory land birds use the refuge mostly in spring through fall, ducks, geese and other migratory waterfowl tend to be more common visitors in the winter, using the open waters for feeding. Bald eagles also visit the refuge in greater numbers in winter. The fish-rich waters that surround the islands also appeal to great blue herons. These tall, statuesque birds have established nesting colonies on several islands. Nesting osprey have also returned to the river in recent decades. Osprey prefer to nest in tall trees close to water, but have adapted to artificial nesting platforms. A visit to the refuge reminds us of the value of restoring our ties with nature, especially in those areas where humans have left a heavy mark. While offering visitors a chance to experience a bit of the wild Ohio, that was almost lost.