Investigating the rate of coevolution between the Pacific Koel and its hosts

The rate of coevolution between a brood parasite and its host can be measured over time if the parasite begins utilising naive hosts. In Australia, the traditional hosts of the brood-parasitic Pacific Koel were the Noisy Friarbird and the Magpie-lark. However, in the 1970s in Sydney, the koel switched to parasitising the Red Wattlebird. Further in the last five years, koels have expanded their breeding distribution south and began parasitising wattlebirds in Canberra. Thus these two sites provide a rare opportunity to observe coevolution in action. I will perform two experiments to test the ability of both old and new hosts to recognise an adult female koel and to recognise and reject foreign eggs. In addition, measurements will be taken to determine if the koel has evolved mimetic eggs or chicks.