Food: Brown and Amadon (1968) found that birds made up 80 percent (by weight) of the food for merlins, insects 15 percent, and mammals 5 percent. Ferguson (1922) examined 298 stomachs and found 4 mammals, 318 birds, and 967 insects. Birds found in the stomachs included small shorebirds, small game birds, and songbirds (which are normally captured in flight). Insect prey consisted of crickets, grasshoppers, dragonflies, beetles, and caterpillars (Bent 1938), while mammals included pocket gophers, squirrels, mice, and bats (Fisher 1893). American kestrel _Falco sparverius_ L 8½″ W 21″ [Illustration] Habitat: The American kestrel is the smallest and most common falcon in North America, occurring in open and semi-open country throughout the continent. In the Rocky Mountain region, kestrels are most abundant on the plains, but do nest up to 8,000 feet elevation in the Douglas-fir, ponderosa pine, and pinyon-juniper forest types (Scott and Patton 1975, Bailey and Niedrach 1965). They have been observed on the highest peaks after the nesting season (Bailey and Niedrach 1965). Nest: Nest sites vary greatly, but kestrels prefer natural cavities or old woodpecker holes. The following nest sites are reported in order of usage: common flicker holes, natural cavities, cavities in arroyo banks or cliffs, buildings, magpie nests, and man-made nesting boxes (Bailey and Niedrach 1965, Bent 1938, Roest 1957, Forbush and May 1939). Nest boxes, approximately 10 × 10 × 15 inches, should be located 10 to 35 feet above ground with a 3-inch entrance hole. Natural cavities or nest boxes should be available along edges of forest openings (Bailey and Niedrach 1965, Hamerstrom et al. 1973, Pearson 1936). Food: Kestrels hunt from high exposed perches overlooking forest openings, fields, or pastures. Food consists primarily of insects (often grasshoppers), small mammals, and an occasional bird (Bent 1938). Barn owl _Tyto alba_ L 14″ W 44″ [Illustration] Habitat: The barn owl inhabits most of the forest types in the United States except the higher elevation types in the Rocky Mountains. They are usually considered uncommon residents because their silent nocturnal habits render them undetectable by most casual observers. Barn owls are also birds of the open country, and adapt readily to areas occupied by man (Marti 1974). Nest: Before the coming of man, barn owls nested in natural cavities in trees, cliffs, or arroyo walls, but now they also nest in barns, church steeples, bird boxes, mine shafts, and dovecotes (Bailey and Niedrach 1965, Reed 1897). Food: Barn owls frequent areas where small mammals are plentiful; mice, voles, rats, gophers, and ground squirrels are major food items. Birds other than those such as house sparrows and blackbirds, which have communal roosts, are only rarely taken (Marti 1974). Screech owl _Otus asio_ L 8″ W 22″ [Illustration]