Bowerbirds make up the bird family Ptilonorhynchidae. The family has 20 species in eight genera. These are medium-sized passerines, ranging from the Golden Bowerbird (22 cm and 70 grams) to the Great Bowerbird (40 cm and 230 grams). Their diet consists mainly of fruit but may also include insects (fed to young),[clarification needed] flowers, nectar and leaves in some species.
The bowerbirds have an Austro-Papuan distribution, with ten species endemic to New Guinea, eight endemic to Australia and two found in both. Although their distribution is centered around the tropical regions of New Guinea and northern Australia, some species extend into central, western and southeastern Australia.
catbirds are monogamous and raise chicks with their mate, but all other bowerbirds are polygamous, with the female building the nest and raising the young alone. These latter species are commonly sexually dimorphic, with the female being more drab in color. Female bowerbirds build a nest by laying soft materials, such as leaves, ferns, and vine tendrils, on top of a loose foundation of sticks. They lay one or two eggs, which hatch after 19 to 24 days, depending on the species.
The most notable characteristic of bowerbirds is their extraordinarily complex courtship and mating behaviour, where males build a bower to attract mates. There are two main types of bowers. One clade of bowerbirds build so-called maypole bowers, which are constructed by placing sticks around a sapling; in some species, these bowers have a hut-like roof. The other major bowerbuilding clade builds an avenue type-bower made of two walls of vertically placed sticks. In and around the bower, the male places a variety of brightly colored objects he has collected. These objects — usually different among each species — may include hundreds of shells, leaves, flowers, feathers, stones, berries, and even discarded plastic items, coins, nails, rifle shells, or pieces of glass.
bowerbirds have traditionally been regarded as closely related to the birds of paradise, recent molecular studies suggest that while both families are part of the great corvid radiation that took place in or near Australia-New Guinea, the bowerbirds are more distant from the birds of paradise than was once thought. Charles Sibley's DNA-DNA hybridization studies placed them close to the lyrebirds however, anatomical evidence appears to contradict this placement and the true relationship remains unclear.