The woylie, or brush-tailed bettong, is a small nocturnal marsupial that plays an important role in maintaining the health of its habitat. Formerly widespread across much of Australia, the woylie declined dramatically following European colonisation. However, extensive conservation efforts throughout the 1970s, 1980s and 1990s brought the species back from the brink of extinction; the woylie became the first mammal in Australia to be removed from threatened species lists as a result of conservation action. Unfortunately the species has once again suffered a population crash with populations estimated to have declined by more than 80% over the past decade. Researchers are racing against the clock to identify the cause of the declines so that appropriate conservation action can be taken.