The Tasmanian subspecies of the Masked Owl, T. n. castenops, is listed as endangered in Tasmania, as a result of habitat loss. It is also included in the Federal Action Plan for Australian Birds 2000, with a recovery outline available as a PDF. Federally, two other subspecies are listed as vulnerable: the northern subspecies, T. n. kimberlii, and the Tiwi Islands' subspecies, T. n. melvillensis, while the southern subspecies, T. n. novaehollandiae, is listed as near threatened. The reasons for population declines vary and need further investigation, as many of the subspecies have not been abundant in the past and may require closer monitoring. These reasons may include: a possible decline in the availability of small mammals as prey, competition with other nocturnal birds of prey, decline in nest site availability, fire regime changes, land-clearing and forestry practices. Read more about why each these sub-species may be declining in their individual recovery outlines (PDF documents).