The courtship behavior of Sanford's bowerbird (Archboldia sanfordi). American Museum novitates ; no. 1935

18 p. : ill. ; 24 cm.Includes bibliographical references (p. 18)."Sanford's bowerbird (Archboldia sanfordi) was discovered in 1950 in the forests of Mt. Hagen, New Guinea. This species, together with the closely related Archbold's bowerbird (A. papuensis) of western New Guinea, for which a new genus was erected in 1940, differs sharply from all other bowerbirds. Nothing was known of the bower-building behavior of either species except for some circumstantial evidence that the bower took the form of a fern mat in A. sanfordi. In that species the male is sooty black, with a golden crown, whereas in the western species the male is blackish gray, with no trace of color on the head. The females of the two species are so similar that they might easily be taken as belonging to the same species. It is this phenomenon that led to the development of the hypothesis that in certain closely related species of bowerbirds the transfer of sexual signals to objects has brought about the secondary loss of sexual plumage in the males. The loss of sexual plumage is postulated to be responsible for the lack of a crest in A. papuensis, although the bower and bower behavior of that species remain to be discovered and analyzed. The male of A. sanfordi builds a bower that is a mat of ferns and vines adorned with snail shells, resin, and strands of gold-colored bamboo. It spends much time arranging these ornaments and the fern stage which appears to be the territory of a single male. The male is adept at making ventriloquistic notes, in crying harshly, and in making noises like the tearing of cardboard. The display is unique. When the female comes to the bower, the male immediately assumes an infantile attitude in which it flattens its body on the fern mat, chews, with its bill mostly open, on a slender vine, and flutters its wings as does a young bird waiting to be fed. The female does not land on the ferns but remains on low perches encircling the bower. The female appears to dominate the male. When she changes perches she hovers noisily over the prostrate male who continues to 'crawl' in her direction for as long as 22 minutes at a time. Copulation was not observed. The biological advantage of this form of display was not determined"--P. 1