Re-introduction of the ‘extinct in the wild’ South Australian mainland tammar wallaby on Yorke Peninsula, Australia

Summary

The South Australian mainland tammar wallaby (Macropus eugenii eugenii), extinct in the wild by the 1930s from land clearing and fox predation, survived only as an unrecognized feral population in New Zealand descended from 19th-century stock, until 1990s genetic studies identified its origin and New Zealand's own wallaby-control plans created an opportunity to repatriate it. Following repatriation of 85 adults and seven pouch young in 2003-2004, Monarto Zoo used Kangaroo Island tammars as cross-foster surrogates to boost reproduction, producing 178 wallabies for release between 2004 and 2007 before a herpesvirus outbreak ended cross-fostering in 2007. Innes National Park on Yorke Peninsula was chosen as the release site for its size and on-site staff, backed by intensive fox baiting since 2003 and a community fox-control program covering 60,000 hectares by 2009. Four hard-release events between 2004 and 2008 released a combined 125 wallabies, but outcomes varied sharply: the first lost 60% within a year mostly to fox predation, the second lost 86% largely to winter starvation before recovering, the third achieved 61% survival, and the fourth's true survival was uncertain from collar failures. By 2010, an estimated 36 to 49 reintroduced wallabies survived at Innes, with confirmed fourth-generation, site-born animals detected despite founder-line survival remaining only around 41%. Major difficulties included fox predation, seasonal nutritional stress, and the herpesvirus outbreak disrupting planned releases. The project rates itself Partially Successful, since after five years it remains unclear whether a truly self-sustaining population has been established.