Geoscience Reference
In-Depth Information
bill. The casque is hollow and composed of keratin. The casque provides an indica-
tion of the age, sex, and status of an individual bird. It is a prominent feature in
many species and poorly developed in others (see Plate XIV). The rhinoceros horn-
bill is named for its red casque that resembles the horn of a rhinoceros. Hornbills
have broad wings and loud calls that can resemble the calls of monkeys. Hornbills
eat almost anything, though some are strictly carnivorous and others frugivores.
Hornbills have a unique nesting behavior. When the female is about to lay, she
finds a crevice or hole in a tree and seals herself inside. Often the male will assist
her. The hole is completely sealed except for a small slit, which is used by the male
to pass food into his mate and their chicks. While in the nest, the female molts
completely. She remains sequestered through incubation and the initial rearing of
the young. The male, often helped by last year's brood, brings fruits, berries, and
insects throughout the entire nesting cycle. Because hornbills are large birds, they
require large expanses of forest. Along with most of West Malesia, hornbills are
found in New Guinea but not Australia. As the forest declines, the populations
become threatened.
Parrots are poorly represented in West Malesia, but are plentiful in East
Malesia. Only three small parrots (the blue-rumped, vernal-hanging, and the blue-
crown hanging parrot) along with several parakeets are present in the rainforests of
West Malesia. Many have a vibrant green plumage and brightly colored heads and
breasts.
Pheasants, partridges, tragopans, firebacks, great and crested argus, and pea-
cock pheasants are some of the many ground-dwelling birds that live in the forests
of West Malesia. Doves and an astounding array of pigeons, including green
pigeons, are abundant on the forest floor and the lower canopy levels. Pittas and
broadbills are small, round ground dwellers with short tails and long legs that
inhabit the undergrowth. Many pittas have blue, green, or red feathers. Broadbills
are less colorful with brown or black feathers with yellow markings.
Myna birds are common in West Malesia. Mynas are dark brown, black, or
gray birds with yellow bills and yellow feet. They all have a white patch on the
underside of the wings. Mynas mimic the calls of other animals in the forest.
Sunbirds, flowerpeckers, spiderhunters, and honeyeaters are small, brightly col-
ored birds. Like the sunbirds of Africa, Asian sunbirds are mainly nectar feeders
with long curved bills. They are bright yellow, red, purple, or olive green. Several
have a metallic sheen. Flowerpeckers are very small and live in the upper canopy.
Spiderhunters are small, mostly yellow birds with large curved beaks used to pick
spiders out of holes. Honeyeaters are the most abundant of the nectar-feeding birds
in East Malesia.
Like Africa, little brown insect-eating birds are the most abundant birds in the
Asian-Pacific rainforest. They tend to travel in mixed flocks composed of many of
the same bird families found in Africa. Bulbuls, Old World Warblers, thrushes, fly-
catchers, shrikes, and a large variety of babblers may be members of a single flock.
Babblers and Old World Warblers are well represented in Asia, with each group
