elk (also known as wapiti) and 40,000 mule deer. Bighorn sheep and mountain goats inhabit the rocky terrain and highest elevations. During the winter, one of the largest bighorn sheep herds in the lower 48 states congregate in the region around Dubois, Wyoming; however, their numbers since 1990 have been diminished due to disease transmitted from contact with domesticated sheep and goats. An estimated 5,000 bighorn sheep are found throughout the forest and a small but stable population of 200 mountain goats reside in the northernmost portions of the forest. Bison and pronghorn antelope are two other ungulates that live on the forest and have sustainable populations. An estimated 300 species of birds are found in the forest at least part of the year. Bald eagle, peregrine falcon, Swainson’s hawk and the prairie falcon are birds of prey that are relatively common. Waterfowl such as Western grebe, Northern pintail, Great blue heron and Barrow’s goldeneye have stable populations and rare sightings of Trumpeter swans are reported. pheasant, ruffed grouse and wild turkey are widely distributed across the open sage lands. Harlequin duck and northern goshawk are generally rare but management plans were implemented to protect various habitats these two species frequent to try and increase their population numbers. Fish found in Shoshone National Forest include at least six species and subspecies of trout including rainbow, brook and brown trout. The Yellowstone cutthroat trout is widespread throughout the Greater Yellowstone Ecosystem, but in the forest is mostly limited to the Shoshone River. The mountain whitefish is also found in the Shoshone River, while the burbot is found in two streams in the southern regions of the forest. There are more than a dozen species of reptiles in the forest including the venomous prairie rattlesnake which can be found at lower elevations. The western painted and the ornate box turtle are turtle species known to exist and about eight species of lizards such as the greater short-horned lizard have been documented. Amphibians such as the Columbia spotted frog and the boreal toad are considered species of concern because of their high susceptibility to disease, habitat loss and human introduced toxins. Boreal toads are found at elevations of between and the Columbia spotted frog can live at elevations as high as in the Greater Yellowstone Ecosystem. Exotic species of fauna such as the zebra and quagga mussels and the New Zealand mud snail