Nest: Although the peregrine falcon is currently considered a cliff-nester, records indicate that it once nested in tree cavities (Goss 1878, Ridgway 1889, Ganier 1932, Bellrose 1938, Spofford 1942, 1943, 1945, 1947, Peterson 1948). The peregrine still uses cavities in broken-off trunks in Europe (Hickey 1942), but the hole-nesting population of America apparently disappeared with the felling of the great trees on which they depended (Hickey and Anderson 1969).
Food: The peregrine falcon feeds primarily on birds ranging in size from mallards to warblers, which are usually stunned or killed in flight. Mammals and large insects form only an insignificant portion of the diet (Bent 1938). White and Roseneau (1970) found remains of fish in the stomachs of peregrines in Alaska, and suggested that fish may be more common in some peregrine diets than the literature indicates.
Merlin
Falco columbarius
L 12″ W 23″
Habitat: The merlin is usually found in open stands of boreal forest, Douglas-fir—sitka spruce, poplar-aspen-birch-willow, ponderosa pine—Douglas-fir, oak woodlands, and saltwater marshes (Craighead and Craighead 1940, Lawrence 1949, Brown and Weston 1961).
Nest: Like the peregrine falcon, most cavity nests for the merlin were reported before 1910, when it was nesting in cavities of poplars, cottonwoods, and American linden trees (Bendire 1892, Houseman 1894, Dippie 1895). The merlin usually uses tree nests built by other large birds (such as hawks, crows, and magpies) but sometimes nests on the ground under bushes or on cliffs and cutbanks.
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).