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

Birds often advertise their quality to potential mates through sexual displays that complement their colorful plumage. Some species use materials to enhance their attractiveness, such as the use of colorful fruits and anthropogenic materials in the display bowers across bowerbirds. Here we report the first observations of anthropogenic materials in sexual displays by two fairy-wren species. On two separate occasions and sites, we witnessed a White-winged and Red-backed male carrying a piece of plastic as a substitute for a flower petal during a petal display, which are used across Malurus to enhance reproductive fitness. 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.