Falconiformes(redirected from Falconiform)
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an order of diurnal birds of prey. The body length ranges from 16.5 cm in sparrow-sized falconets to 112 cm in vultures. The bill is hooked, and the base of the culmen is covered with cere. The talons are sharp and hooked; they are blunt only in vultures. The dense plumage is dull in coloration: black, gray, brown, and rusty tones predominate. The long pointed wings are adapted to precipitous flight. In some species the wings are wide with a slit apex, making it possible for the birds to soar for hours on ascending air currents.
There are two suborders: Cathartae and Falcones. Cathartae comprises only one family—Cathartidae. Falcones has four families—Pandionidae (with the single species Pandion haliaetus), Accipitridae, Falconidae, and Sagittariidae (with the single species Sagittarius serpentarius). The USSR has 52 species. The birds are distributed throughout the world except in Antarctica and on certain oceanic islands. They are found in all natural zones, from the tundra to the desert and tropical forests. Many are sedentary birds; others make long or short migrations. The birds are monogamous, nesting once a year on the ground, on rocky ledges and coastal cliffs, in trees, or in man-made structures. Many do not build nests but occupy those of other birds. Large species produce a clutch containing one or two eggs; the clutches of small species may contain as many as six or seven eggs. The incubation period ranges from 28 days for falcons to 55 days for vultures. The young birds leave the nest in one to three months.
The birds are mostly active during the day; only a few species are active at twilight. Vultures sometimes feed on moonlit nights, eating carrion found by day. Vultures of the genus Gypohierax, however, feed on the fruits of the oil palm. The diet consists of animal substances. Some species are almost omnivorous. Honey buzzards feed principally on insects, ospreys on fish, and short-toed eagles on reptiles. Some species eat mostly birds or mammals. The birds seek their prey while perched in a high place, catching the prey in the air or on the ground. Some soar for a long time or survey their hunting territory regularly from the air.
The birds play an important role in controlling the number of vertebrates, including destructive rodents. By destroying weak or diseased animals, they make the population healthy. Only a few species, for example, the marsh harrier and the goshawk, inflict losses on the hunting industry.
REFERENCESPtitsy Sovetskogo Soiuza, vol. 1. Edited by G. P. Dement’ev and N. A. Gladkov. Moscow, 1951.
Zhizn’ zhivotnykh, vol. 5. Moscow, 1970.
A. I. IVANOV