Lord Howe boobook than both the New Zealand and Norfolk Island subspecies. The Lord Howe boobook was restricted to Lord Howe Island where it inhabited the native forests as well as occurring around the settlements. Exactly when the Lord Howe boobook became extinct is uncertain. Boobook calls were apparently heard on the island until the 1950s, but during the 1920s boobooks from near Sydney in eastern Australia had been introduced, along with barn owls and masked owls, in an unsuccessful effort to control the black rats that had overrun the island. The rats had been accidentally introduced in June 1918 with the grounding
Southern boobook treated Australian and New Zealand boobooks, along with several taxa from Indonesia and Papua New Guinea, as one species—"Ninox novaeseelandiae"—with 16 subspecies. In his 1968 book "Nightwatchmen of the Bush and Plain", Australian naturalist David Fleay observed that the boobooks from Tasmania more closely resembled those of New Zealand than those from mainland Australia, though he followed Mees in treating them as a single species. The southern boobook was split from the Tasmanian boobook and morepork in volume 5 of the "" in 1999, though several authors, including Australian ornithologists Les Christidis and Walter Boles, continued to treat the three