Bowerbirds and catbirds make up the bird family Ptilonorhynchidae. The family has 20 species in eight genera. 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 polygymous, 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.
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. The males spend hours arranging this collection. Bowers within a species share a general form but do show significant variation, and the collection of objects reflects the biases of males of each species and its ability to procure items from the habitat, often stealing them from neighboring bowers. This hypothesis is not well supported because species with vastly different bower types have similar plumage. Borgia has suggested[citation needed] that the bower functioned initially as a device that benefits females by protecting them from forced copulations and thus giving them enhanced opportunity to choose males, and benefits males by enhancing female willingness to visit the bower. Evidence supporting this hypothesis comes from observations of Archbold's bowerbirds that have no true bower and have greatly modified their courtship so that the male is limited in his ability to mount the female without her cooperation. In toothbilled bowerbirds that have no bowers males may capture females out of the air and forcibly copulate with them. Once this initial function was established bowers were then co-opted by females for other functions such as use in assessing males based on the quality of bower construction. Recent studies with robot female bowerbirds by Patricelli and collaborators have shown that males react to female signals of discomfort during courtship by reducing the intensity of their potentially threatening courtship.[citation needed] Coleman and colleagues[who?] found that young females tend to be more easily threatened by intense male courtship, and these females tend to choose males based on traits not dependent on male courtship intensity.
Bower bird
Bower bird
Bower bird
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. Sibley's DNA-DNA hybridization studies placed them close to the lyrebirds[citation needed]; however, anatomical evidence appears to contradict this placement[citation needed] and the true relationship remains unclear.