National Geographic : 1933 Jul
THE NATIONAL GEOGRAPHIC MAGAZINE DUCK HAWK (Falco peregrinus anatum) The duck hawk, finest of the falcons of our continent, lives in regions where cliffs furnish it aeries. Truly a master of the air, it kills at will, and its food is composed almost entirely of birds. Resting on a commanding perch or fly ing easily, the hawk, when its appetite is aroused by some luckless bird, descends with a rush of wings so swiftly as almost to elude sight, and strikes its unfortunate victim like a veritable thunderbolt. Ducks, shore birds, robins, meadowlarks, flickers, pheasants, grouse, pigeons, and many others have been recorded as its victims. When it has tiny young, it obtains war blers, sparrows, and other small birds to feed them. No form of bird is safe from it, as it has been known even to capture the agile chimney swift. A duck hawk comes nearly every winter to the old Post Office Department tower in Washington, and lives on pigeons captured as they fly over the grounds of the Smithsonian Insti tution or above the near-by buildings. Mammals are seldom taken. The duck hawk usually places its nest on a cliff, often in a spot where it is prac tically inaccessible. Occasionally it resorts to large hollows in trees, or very rarely to old nests of eagles or hawks. The only nesting material consists of whatever rub bish may have accumulated on the chosen site, this usually including bones and other fragments from birds the duck hawk has eaten. Three to five eggs are laid, four being the usual number. These are creamy or yel lowish white, irregularly blotched, streaked, or otherwise heavily marked with various shades of bright brown. The parents are noisy during the breed ing season, uttering quick, cackling calls. When their nests are approached, they circle rapidly about, harrying unmercifully other birds that chance to pass, and even killing ruthlessly when enraged. The duck hawk nests from Alaska and the west coast of central Greenland to Baja California, Kansas, and Maryland. In winter it ranges south to Panama. Peale's falcon, Falco peregrinus pealei, a darker race, nests on the Aleutian and Commander Islands, coming south in win ter to Oregon. Allied races are found in the other continents of the world. GYRFALCON (Falco rusticolus) This hunting falcon of the north in early days was the type most prized by the dev otees of the sport of falconry. Swift in flight and possessed of almost endless en durance, these birds were desired above all other hunting hawks. They range far beyond the limits of tree growth, apparently to the limits of land. They become so accustomed to resting on the ground or on rocks that in captivity they actually seem to prefer such locations to a perch. The gyrfalcons of North America ap pear to like birds better than other food, capturing them ordinarily on the wing. In the far north they often nest in the vicinity of colonies of auks, great piles of whose bones accumulate beneath the gyrfalcon homes. From Labrador to Alaska these falcons are the scourge of the ptarmigan. They also capture gulls, guillemots, shore birds of various kinds, and snow buntings, as well as lemmings and Arctic hares. On St. George Island, one of the Pribilof group in Bering Sea, Hanna records that one winter gyrfalcons came in abundance and nearly exterminated the little wren and the rosy finches. The gyrfalcon nests on ledges on the face of cliffs, placing its eggs on accumu lations of its own pellets, or, where there is woody vegetation, it sometimes occupies nests of sticks. The eggs, usually three or four, are creamy white, very heavily marked with reddish brown, and are among the most handsome eggs of their group. Nesting may come in May in the far north, so that the nests are frequently hung with icicles. The races of gyrfalcons found in North America are in some confusion because of the considerable variation in color among these birds. In Greenland there is found the white gyrfalcon, Falco rusticolus candi cans, which also has a dark phase in which the plumage is mainly gray. This race may breed also in eastern Arctic America, and is casual in winter south to British Columbia, Montana, and Maine. A darker form, varying from gray to nearly black, known as the black gyrfalcon, Falco rusti colus obsoletus, nests from Point Barrow to Labrador, and in winter ranges south into the northern United States.