Darwin’s finches on the Galápagos Islands are once again providing insights into the theory of evolution, with two studies investigating their dealings with the parasitic avian vampire fly (Philornis downsi). One study investigated which species of finch proved to be the most successful hosts for the flies, while a second study looked at how the birds cope with being infected by the parasites. The insights will help researchers to maintain the finch population while also providing strategies for dealing with other parasitic species around the world.