Bowerbirds
The bowerbird is the supreme artists among birds. Not only do the males
construct elaborate structures decorated with colorful objects - fruits, berries, fungi, tinfoil and bits of plastic—but some even paint them with natural pigments applied with a tool or “paintbrush” held by the bill.
Nine bowerbirds live only in New Guinea; seven only in Australia and two are com-moon to both. Most inhabit wet forests, up to 4,000m (13,000ft) above sea level in the case of the little-known Archibald’s bower-bird, discovered as late as I- 94o. Many are extremely localized, like the Delbert bower-bird, confined to the Albert Mountains of Papua, New Guinea, and the Golden and
Tooth-billed bowerbirds, found only in rainforests above Yom (2,95oft) on and around the Atherton Tableland of Queens-land, Australia. Other species, notably New Guinea’s flamed bowerbird and Australia’s Spotted and Great Gray bowerbirds have extensive continuous ranges. While most others have patchy broken distributions.
Bowerbirds have long been considered close relatives of birds of paradise and recently several ornithologists placed both groups in the family Paradisaeidae. Ana-topical and behavioral studies and the analysis of genetic characters indicate very strongly, however, that the two groups form distinct families. Some genetic studies have indicated closer relationships between bowerbirds. Lyrebirds and Australian scrub-birds than previously acknowledged.
Bowerbirds are stout, strong footed, heavy-billed birds ranging in size from that of a starling to that of a medium crow. As much a part of the physical appearance of adult male bowerbirds is the court or bower. These remarkable external secondary sexual characters—only discovered in 18 70 —are created to impress females, and possibly also to intimidate rival males, and have nothing to do with nesting, which is entirely
The females’ concern. Recent studies of the Satin bowerbird indicate that bower building is not innate but is learned behavior. Young males start with inferior bowers but gradually improve them as they gain experience. Males of bower-tending species are promiscuous, attracting many females toothier bower by calls and mating with as many as possible. Most such males are very brightly colored; glimmering gold, or orange, and black as in the Flamed. Delbert, Regent and Archibald’s bower-birds iridescent blue-black in the well-known Satin, completely brilliant yellow and golden-olive in the Golden or generally brown with contrasting orange or yellow crest like most of the Gardener bowerbirds. The “avenue” bower building Spotted, Great Gray, Fawn-breasted and Lauter-bach’s bowerbirds of grasslands and more arid woodlands are generally drab gray or brownish with small pinkish nape crests.
An important generalization is that species with more colorful males build modest bowers while drabber ones build bigger complex structures (see box). Females of promiscuous species wear drab camouflage, being predominantly brown, olive or gray, often with barring or spotting. The sexes of White-eared, Spotted and Green catbirds are similar, being generally green with. White spotting on breast, wings, tail and about the head or throat. Sexes of the presumed pro-miscues Tooth billed bowerbird are also identical, being olive brown above and heavily streaked brown on dirty white below. Male Tooth bills clear a forest floor “court” of litter and lay decorative green leaves on it, and they call almost con-tenuously at it to attract females.
Males of promiscuous species are long-lived, taking up to seven years to attain adult plumage from their initial female coloration, whereas females may breed after two years. Some Satin bowerbird bower sites have been used for nearly 50 years.
Most bowerbirds are predominantly fruit eaters, but insects, vegetable matter and some animals are also taken. In winter some of the avenue-building bowerbird species regularly form flocks which may be serious pests to commercial fruit crops, and Satin bowerbird flocks will ground feed on grasses. Most other polygamous species appear to be sedentary and probably solitary.Toothbilled bowerbirds eat considerable amounts of leaves and succulent stems in winter, having a stout “toothed” bill forbearing and chewing leaves. Until recently. Promiscuous male bowerbirds were presumed to form breeding colonies or leeks, their bowers being clustered in associated congregations, but no confirmation of this exists. Recent studies show that the Regent, Satin, Fawn-breasted, Macgregor’s and Golden bowerbirds certainly do not, their bowers being evenly distributed throughout suitable habitat. In those promiscuous species which have been studied, females defend only their nest site and males only the immediate vicinity of the bower. In the monogamous catbirds an all-purpose territory is maintained year round.
Birds of paradise are so named because of the bizarre appearance of most males, which have fantastic feather and plume structures and wonderful coloration, much of which is iridescent.
Most species are confined to New Guinea where the family doubtless originated, but the Paradise crow and Wallace’s standard-wing are confined to the Moluccas islands and the Paradise and Victoria’s riflebirds to eastern Australia. The Magnificent riflebird and the trumpet bird ranges also just reach Australia from New Guinea. Some New Guinea species have extensive lowland distributions but most have restricted and/or patchy ranges in the mountains at definite altitudinal zones. A few are confined to off-shore islands. Most species are wet forest birds although a few occur in sub-alpine woodlands, lowland savanna or mangroves.