Broadbills

Broadbills

Broad Bills are sturdy birds whose squat appearance is accentuated by a rather short, square tail, except in the Long-tailed broadbill which has a fine-pointed tail. The family is named for the great width of the mouth, which reaches a grotesque extreme among passerines in the outsize pink bill of the Dusky broadbill. Broadbills inhabit chiefly the interior of evergreen or semievergreen broad-leaved lowland forests. Only two species are exclusive mountain dwellers although Long-tailed and silver-breasted broad hills are restricted to mountainsides in. inner tropical Southeast Asia.

No genus is common to both areas of the thebroadhills’ distribution and the diminutive, mainly brown, ventrally streaked Black-capped, Rufous-sided, and Cray-headed broad bills look so different from their gaudy Asian relatives that they were long classified as flycatchers- -the shape of the bill, notwithstanding. Anatomical studies exposed this apparent error, adding broadbills to the Afri-can bird stock in 1914 though 19 more years elapsed before the discovery of the African green broadbill. Three genera are green with black, blue, or yellow on the head, wings, belly, or tail. Long-tailed, Hose’sand occasional male Green broadbills have all of these colors. The Banded broadbill is wine-red with a blue bill, and other species are black with areas of red, lilac, yellow, and/or white. Black is replaced by rich chestnut in the Philippine broadbill.

For all their color, however, bright plumages are not especially conspicuous in forest and the most prominent feature of, for example, the Black-and-red broadbill, sitting in the shade of a waterside thicket, is its almost luminous pale blue and yellow bill(which fades after death and cannot be appreciated in museum specimens). Several species, including those of the genusSrnithorrris, also have on their backs one or more white, yellow, or orange flashes on a dark background, exposed during flight, andSilver-breasted broadbills have a bright chestnut rump, often fluffed out when they perch.

In most species the bill is both wide and rounded along its sides, perhaps to aid the aerial capture of large arthropods by rather slow-moving birds. It is also variously hooked, almost hawklike in the Duskybroadbill which has been seen snatching bigorthopterans in an upward leap from the perch. This bill form is otherwise found only in trogons and frogmouths, which share the broadbill habitat and feed similarly. Other foraging modes include “flutter-snatching” from foliage and hark, and a Banded broad-bill is recorded capturing a lizard. Most species forage at mid-levels of the forest but the Dusky broadbill is a high-canopy bird. Two others, the Black-capped in Africa and Black-and-red in Asia, inhabit forest edges and thickets and will go to the ground to feed. Besides taking insects in their water-side habitat, Black-and-red broadbills sometimes also capture aquatic organisms.

The African green broadbill and Calyp-to mean species alone have hills that are straight-sided but still very wide at the base. The latter feed largely on fruit and while these two genera are not necessarily closely related there is evidence that the African green broadbill also takes much plant material.

Green broadbills often advertise their presence by cooing rattles, and pairs will drive members of the same species of small, defendable fruit sources. At larger sources, several may gather, as well as Hose’s broad bills. These two live mainly in lowland forests where the fruit is scattered and like other fruit-eating birds, they must wander over a sizable area if they are to find sufficient food.

Green broadbills even disperse at night. Their much larger relative, Whitehead’sbroadbill, lives exclusively above 200 m (4,000ft) in the montane forest where fruit sup-plies may be more stable.

Insect-eating broadbills are more sedentary. Banded and Black-and-yellow broad bills space themselves through the forest. Their presence is advertised with loud, explosive trilling calls, invariably answered by neighbors.

Most others are less vociferous. Smithornis species are peculiar in producing a nonvocal croaking noise, apparently during short, circular flights. This sound is produced by vibrating wings. These flights are thought to have a court-ship function but the noise produced by the Black-capped broadbill carries up to 6om(about 20(.)ft) and could also be a territorial signal.

Most species give a clear two-syllable whistle, most often when foraging groups assemble after breeding. These groups are usually small but as many as 20 Silver-breasted broadbills may gather and up to 26Long-tailed broadbills have been counted progressing together through mountain forests in North Sumatra. Only the Duskybroadbill is permanently gregarious and occurs in noisy parties of up to To strong.

Broadbill nests are large, pear-shaped bags with a crudely overhung side entrance, slung by a long woven cord of nest material from an isolated branch, creeper, or frond tip. They are roughly made, of all kinds of vegetation, drawn out below into a wispy head.

Leafy creeper, lichen and moss, and leafy liverworts are often included and it is common for the nest chamber to be lined with fresh green leaves. Usual nest sites are well off the ground but the Green broadbill, whose nest is broadly strapped over its support, invariably builds low, as do Smithornisspecies.

Black-and-red broadbills often use a dead stump or snag in a stream, and will sometimes take advantage of a service wire over a stream or road. There are no records of helpers attending broadbill nestlings, but the Dusky broadbill flock cooperates in nest construction.

In Malaya, Black-and-yellow broadbills have been seen feeding fledglings of the Indian cuckoo and are presumed to be a brood host of this cuckoo. The one definitely identified egg of the local subspecies of the Indian cuckoo is a fairly close match for the broadbill egg in color and size.

Though only casually studied. most broadbills are frequently seen and even the least known, the Philippine and African green, are unlikely to prove rare once their habitats have been explored. With the rest of their communities, most nevertheless face the threat of habitat destruction.

See more: Woodpeckers