Interpopulation differences exhibited by Spotted Bowerbirds Chlamydera maculata across a suite of male traits and female preferences

Male Spotted Bowerbirds Chlamydera maculata build and decorate structures, bowers, that act as targets for female choice. Bower construction, orientation and distribution all differed between two populations, as did rates of intrasexual aggression. Although there was a broad similarity in classes of decorations used on bowers, the exact types and positioning varied between populations. For two intensively studied populations, different decorations appeared to be the best predictors of mating success. In both populations, male owners of high-quality bowers obtained higher mating success. Male display intensity differed dramatically between populations, and females appeared to differ in the attention that they paid to the male's own display movements. Females also differed in the position that they took to observe a male's display. These variations suggest that differing selective forces may be acting on the elaboration of extreme male display traits across populations. I comment on how this variation can be used to illuminate current hypotheses for the evolution of bowers.