Use of anthropogenic material for extended ornamented phenotype in two fairy-wren species

Abstract

Birds often advertise their quality to potential mates through sexual displays that complement their colourful plumage. Some species use materials to enhance their attractiveness, such as colourful fruits and anthropogenic materials in display arenas in bowerbirds (Ptilonorhynchidae). Here we report the first observations of anthropogenic materials in sexual displays by two fairy-wren Malurus species. On two separate occasions and sites, we witnessed a male White-winged and male Red-backed Fairy-wren carrying a piece of plastic as a substitute for a flower petal during a petal display. These displays are used across Malurus species and are thought to increase fitness, particularly through greater extra-pair paternity. Given increasing plastic pollution globally, the use of anthropogenic materials as part of extended phenotypes in birds and other animals will likely increase and it will be important to understand the effect this has on populations.