Behaviour_and_ecology Bowerbird

female satin bowerbird

uy , collaborators have shown mate-searching females commonly visit multiple bowers, returning male several times, watching elaborate courtship displays , inspecting quality of bower , tasting paint male has placed on bower walls. many females end selecting same male, , many under-performing males left without copulations. females mated top-mating males tend return male next year , search less.

bower of great bowerbird

ernest thomas gilliard suggested transfer effect, in claimed there inverse relationship between bower complexity , brightness of plumage. gilliard suggests there evolutionary transfer of ornamentation in species, plumage bowers, in order reduce visibility of male , thereby vulnerability predation. hypothesis not supported because species vastly different bower types have similar plumage. others have suggested bower functioned device benefits females protecting them forced copulations , giving them enhanced opportunity choose males , benefits males enhancing female willingness visit bower. evidence supporting hypothesis comes observations of archbold s bowerbirds have no true bower , have modified courtship male limited in ability mount female without cooperation. in toothbilled bowerbirds have no bowers, males may capture females out of air , forcibly copulate them. once initial function established, bowers co-opted females other functions such use in assessing males based on quality of bower construction. recent studies robot female bowerbirds patricelli , collaborators have shown males react female signals of discomfort during courtship reducing intensity of potentially threatening courtship. coleman , colleagues found young females tend more threatened intense male courtship, , these females tend choose males based on traits not dependent on male courtship intensity.

the high degree of effort directed @ mate choice females , large skews in mating success directed @ males quality displays suggests females gain important benefits mate choice. since males have no role in parental care , give nothing females except sperm, suggested females gain genetic benefits mate choice. has not been established, in part because of difficulty of following offspring performance since males take 7 years reach sexual maturity. 1 hypothesis evolutionary causation of bowerbuilding display hamilton , zuk s bright bird hypothesis, states sexual ornaments indicators of general health , heritable disease resistance. doucet , montgomerie determined male bowerbird s plumage reflectance indicates internal parasitic infection, whereas bower quality measure of external parasitic infection. suggest bowerbird mating display evolved due parasite mediated sexual selection, though there controversy surrounding conclusion.

this complex mating behaviour, highly valued types , colors of decorations, has led researchers regard bowerbirds among behaviorally complex species of bird. provides of compelling evidence extended phenotype of species can play role in sexual selection , indeed act powerful mechanism shape evolution, seems case humans. inspired seemingly extreme courtship rituals, charles darwin discussed both bowerbirds , birds-of-paradise in writings.

in addition, many species of bowerbird superb vocal mimics. macgregor s bowerbird, example, has been observed imitating pigs, waterfalls, , human chatter. satin bowerbirds commonly mimic other local species part of courtship display.

bowerbirds have been observed creating optical illusions in bowers appeal mates. arrange objects in bower s court area smallest largest, creating forced perspective holds attention of female longer. males objects arranged in way have strong optical illusion have higher mating success.