Island and mainland populations of animals can experience substantial differences in their interactions with other species. One possible outcome of island colonisation is a reduction in parasite pressure on the island in comparison to the mainland, leading to ecological release for the host. We carried out a molecular survey for avian malaria (Plasmodium and Haemoproteus spp.) infections in Capricorn Silvereyes (Zosterops lateralis chlorocephalus) from a small island population previously thought to be free from the disease (Heron Island, Australia). We also screened mainland Silvereyes (Z. lateralis cornwalli) that arrived on the island as vagrants. Nested-PCR revealed an avian haemosporidian blood parasite prevalence of 6.2% in resident island Silvereyes and 100% for mainland vagrants (n=3). We report the first evidence of avian malaria infection in Silvereyes from Heron Island, indicating that island residents have not entirely escaped their avian malaria parasites. Additionally, we suggest that mainland vagrants play important roles in maintaining the stability of Heron Island's avian parasite community.