Some nineteen genera may be admitted, from the Ethiopian, Indian, and Australian Regions, with about seventy species, more than thirty of which occur in each of the first two areas; a couple inhabit Celebes, and one ranges over the Moluccas and Papuasia to the Solomon Islands. None inhabit Australia.
The somewhat scanty plumage is usually black, white, and grey; but a greenish or bluish tinge, or rufous heads and lower parts are not unfrequent. Crests are present, except in Bucorvus; Ceratogymna has a gular wattle; Berenicornis and Ortholophus exhibit long upcurved loral plumes; while the orbits and throat are more or less naked, and usually of brilliant colours, these with the bill and casque being often a distinguishing mark between the sexes. The last develops gradually in the duller young.
Rhinoplax vigil of the Malay countries, termed the Helmet Hornbill, has a line down the back and the neck naked and red. The casque is yellow in front and red behind, and is much used by Eastern artists for carving and making brooches. Berenicornis comatus, of the same districts, has a moderate black keeled casque, and bare blue orbits and throat. The female exhibits less white. Bycanistes buccinator of East Africa has a large blackish furrowed casque and purple naked areas. Lophoceros nasutus of North-East and West Africa, has the bill and rudimentary casque black, with a yellow streak on the maxilla and several oblique yellow ridges on the mandible, the bare orbits apparently grey. In the female the bill shews red in place of black.
Fig. 83.–Plait-billed Hornbill. Rhytidoceros undulatus. × ⅕-⅙. (From Nature.)
Ceratogymna elata of West Africa has the gular wattle, orbits, and bare throat blue, with red on the first and a median line of feathers on the last, and an abrupt, high whitish casque, which is black at the base in the male. The hen has a rufous head and neck. Rhytidoceros plicatus of Papuasia and the Moluccas has a reddish and white casque with obliquely overlapping plates, pale blue naked orbits and throat. The head and neck are chestnut in the male, black in the female. Cranorhinus cassidix of Celebes has a red casque, high in front and rounded posteriorly over the skull; both mandibles are yellow with red bases, and exhibit grooved plates, the bare parts being chiefly blue with a black bar on the throat. The head and nape are chestnut and black in the respective sexes, the hen having the casque yellower. Penelopides manillae of the Philippines has the moderate, compressed casque transparent brown, and the naked areas white, becoming purplish in the female. Anthracoceros coronatus of India and Ceylon has a large yellow subcrescentic casque blotched with black, a bare white throat and blackish orbits, the latter being white in the hen. Dichoceros bicornis (Fig. 82) of India and the Malay countries has a large yellowish-red casque, hollowed and ending in two points anteriorly, which shews black markings in the male; the naked orbits are pinkish. Buceros rhinoceros of the Malay Peninsula and Indo-Malay Islands has a large red, orange, and black casque, curved up in front, and red orbits; the female having less black on the former. Bucorvus (Bucorax) has a large black casque, nearly or quite closed in B. cafer of South and East Africa, but open anteriorly and ridged in B. abyssinicus of North-East and West Africa. In the respective species the naked parts are red and blue in the male, blue and purple in the female. Some writers adopt a Sub-family Bucorvinae for this genus.
The fossil Cryptornis of the Upper Eocene of France is referred to the Hornbills.
Fam. VI. Upupidae.–Sub-Fam. 1. Upupinae.–This consists of a single genus with five similarly-coloured graceful species, which have the beak long and slightly arched, the metatarsi short and scutellated throughout, the toes rather long and the claws curved. The third and fourth digits only are joined at the base. The broad wing has ten primaries and an equal number of secondaries, the short, square tail has ten rectrices, the nestlings possess a little down. Otherwise the structure resembles that of Hornbills.
Generally found solitary or in pairs, Hoopoes stalk proudly along the ground, nodding their heads, expanding and contracting their crests, and uttering the soft reiterated "hoop" or "hoo," from which is derived their name. Besides probing the soil, the bird taps the ground with its bill or foot, and some persons think that worms are brought to the surface by the vibration; but it will also tap any perch, whether on branch, stump, or wall. The food consists of flies taken on the wing, insects generally, and worms; individuals being frequently observed climbing rocks or branches of trees in search of prey, and carefully examining heaps of refuse. Before being swallowed the larger objects are smartly rapped on some hard surface, and most are tossed into the air. The flight is strong, undulating, and seldom protracted, though Hoopoes often escape from Hawks; they can also run rapidly. The nest, placed in holes in trees, walls, or rocks, consists of a little straw or a few twigs, with some feathers or hair; it is always, however, marked by the addition of ordure to the lining, and sites are on record in coffins or decaying bodies.[[229]] During incubation the cock feeds the hen, who hardly stirs from her post; the eggs number from four to seven, and are pale greenish-blue with distinct pores. These birds are fond of dusting themselves in loose soil; the male is decidedly pugnacious, except in captivity; and the flesh is considered a delicacy in Southern Europe. Arabs venerate them and ascribe to them medicinal properties. Most persons are familiar with the story of Allah granting to Epops a golden crest, exchanged afterwards at the bird's request for one of feathers.
