National Geographic : 1933 Jul
EAGLES, HAWKS, AND VULTURES EVERGLADE KITE (Rostrhamus sociabilis plumbeus) This resident of fresh-water marshes is suggestive in form, white rump, and method of flight of the much larger, lon ger-tailed marsh hawk. It enjoys soaring, frequently ascending to considerable alti tudes, but does not have the graceful, accomplished flight of our other kites. The everglade kite is sociable, and, where plentiful, a hundred may be observed to gether. In Florida, however, it has been so reduced that flocks are unusual. The birds utter a rasping, chattering call of little volume, and are especially noisy during the mating and nesting season. For food this kite depends on the large fresh-water snails belonging to the genus formerly called Ampullaria, known now as Pomacea. The kite seizes them in its long claws and bears them away to some low limb or mound, where, with the slen der, sharply hooked bill, it draws the snail from its shell. Occasionally the kite extracts its food as it flies, dropping the shell when empty. I have seen accumulations of dozens of the shells gathered beneath favored perches. So far as known, this kite eats no other food. Such extreme specialization in diet is unusual among birds. The slender form of the bill and the claws, developed for this peculiar habit, is remarkable. The everglade kite in Florida nests from January to May, the season varying lo cally. The nest is made of small twigs placed in a myrtle or other bush, in the top of a clump of saw grass, or, rarely, in a tree, being usually at only a few feet elevation and ordinarily above water. The eggs number two to five or rarely six, two or three making the usual set. The ground color is pale greenish white spotted with rusty brown, the spots in most cases being so numerous as almost to conceal the lighter base. The young of the everglade kite are fed on the same large snails relished by the adult, the par ent usually bringing food in the crop and feeding its family by regurgitation. In the United States the everglade kite is found only in Florida. To the south it ranges in Cuba, eastern Mexico, and Central America, and a closely allied race occurs in South America as far as Ar gentina. MARSH HAWK (Circus hudsonius) The marsh hawk, an inhabitant of open country, ranging over prairie regions, grasslands, and cultivated fields, is marked by its slender form, long tail, and a promi nent white spot on the rump. Except dur ing migration or in mating season, this bird seldom flies far above the ground for any great length of time. It is entirely predatory, feeding on mice, ground squirrels, and other small mam mals, as well as snakes, lizards, frogs, and insects. In addition, it captures a good many ground-inhabiting birds, especially in summer and fall, when young birds are about. At times it kills game birds and in some localities, particularly where pheas ants are stocked, the marsh hawk has proved a pest. In general, however, it is beneficial, and should not be destroyed except where it is found to be actually injurious to game. A FEATHER RUFF ADORNS THIS HAWK As a peculiar feature, the face in this species is surrounded by short, stiffened feathers forming a ruff like that found in owls, a feature that is present in no other group of hawks. The marsh hawk places its nest on the ground, usually in a marsh or on a prairie, ordinarily at the foot of a bush or a clump of grass, and in marshy ground on a tussock. It is composed mainly of dried weed stems and grass, sometimes with a foundation of twigs, lined with fine grasses and feathers. From four to six eggs constitute a set. These are pale greenish or bluish white in color, usually without markings, though at times blotched and spotted with brown. The male is attentive to the female during incubation, bringing her food, which she often rises to seize in the air as he drops it. As is often the case with ground-nesting birds, the young wander about on foot near the nest before they are able to fly. The marsh hawk breeds from north western Alaska, central Quebec, and New foundland south to northern Baja Cali fornia, southern Texas, and southeastern Virginia. In winter it is found from British Columbia and the northern United States south to the Bahamas, Cuba, Haiti, Puerto Rico, and Colombia.