Southern boobook age. Brushtail possums ("Trichosurus" spp.) and introduced cats and rats raid the nests for nestlings and eggs, and raptors such as the brown goshawk ("Accipiter fasciatus"), grey goshawk ("Accipiter novaehollandiae"), Australian masked owl ("Tyto novaehollandiae"), and probably powerful owl ("Ninox strenua") seize young birds. Juvenile southern boobooks are at greater risk after bushfires and have perished after being tangled up in dodder ("Cassytha") or bidgee-widgee ("Acaena novae-zelandiae"). The southern boobook generally preys on mice, insects, particularly nocturnal beetles and moths, and birds the size of a house sparrow ("Passer domesticus"). A higher proportion of its diet is invertebrates compared with
Southern boobook to "N. connivens". Genetic and call analysis show the Christmas boobook ("N. natalis") to be very close to the Australian populations of the southern boobook, leading Gwee and colleagues to suggest it be reclassified within this species. Gwee and colleagues found that boobook populations on larger mountainous islands were more distinct from Australian stock, while those on flatter smaller islands were much more similar, suggesting that these locations were colonised much more recently after previous populations had become extinct. Eleven subspecies of "Ninox boobook" are recognised in version 7.3 of the IOC World Bird List, published in July 2017: The