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CHAPTER III AFFECTED ENVIRONMENT I cliff or series of cliffs 60 to 90 meters (200 to 300 feet) in height. While peregrines may forage up to 27 kilometers (17 miles) from their nesting cliffs, hunting habitat is generally found within 16 kilometers (10 miles) of the nest. Preferred hunting habitat appears to be wetlands, riverbottoms, meadows, croplands such as hayfields, grainfields, orchards, and areas such as gorges, mountain valleys, and lakes over which prey are vulnerable. Open meadows and riparian areas appear to have particular importance to peregrines during the early part of the nesting season. As these areas may become snow-free sooner than other vegetative types, prey species may concentrate in these habitats, providing a more readily available food supply (Service 1984). Little is known of postbreeding movement of adults or immature peregrines, but individuals are occasionally reported in this region during the winter season. Although they are frequently associated with large rivers and wetland areas during this period, preferred wintering areas are largely undocumented. A number of peregrine falcon eyries are currently located throughout the Upper Basin. At least three eyries occur on the Yampa River. Two others occur on the Dolores River. Along the Colorado River, at least eight eyries are located above the Green River confluence, approximately seven near or below the Green River confluence, and eight within the Lake Powell area. Bald eagle. Nesting bald eagles are associated almost exclusively with lakes, rivers, or seacoasts. Fish are generally the major item in their diet, ' but they will also feed on waterfowl, small mammals, and carrion. Adults tend to use the same breeding area and often the same nest each year. The nests are primarily in trees and, to a lesser extent, on cliffs or (rarely) on the ground. A number of bald eagle nests are currently located within the Upper Basin, although not all of them have been reproductively successful in recent years. One successful nest occurs on the Yampa River, and at least two nests are located on the White River. Another nest occurs on the Little Snake River. An additional eagle nest occurs on the main Elk Creek and one other on the Roaring Fork River. Along the Colorado River the only currently active bald eagle nest in Utah is located near Westwater. This nest has successfully fledged young during the past 3 years. In Colorado, approximately four nests , are located near Rifle, and one nest occurs near Grand Junction. These sites have not been successful in recent years, although eagle pairs appear and breeding activity has occurred each year. In addition to these sites, there are a number of areas along the Colorado River at which prenuptial activity ' has been noted, but no successful breeding has been documented so far. Wintering bald eagles occur throughout the country but are most abundant in the west and mid-west, usually near open water where they feed on fish and waterfowl. The major rivers of the Upper Basin provide winter roosting areas for bald eagles. Winter concentrations occur on the Colorado River below Grand Junction, near the Colorado-Utah State line, near the town of Westwater, and along various parts of Lake Powell. On the Green River, winter roosts are located below Flaming Gorge Dam, near the Colorado-Utah State line, and near the communities of Ouray and Green River. III-22 1