Norfolk boobook morepork, being a small brown hawk owl with mottled plumage. It was smaller, darker and more reddish in colouring than the Australian subspecies, with much spotting. However, it was slightly larger than the nominate subspecies from New Zealand; female boobooks are larger than the males, with New Zealand females comparable in size to Norfolk Island males, a factor which gave rise to sexing difficulties with hybrid birds in the conservation management program. The owl inhabited the island's subtropical rainforest, which was largely cleared in the 19th century following human settlement. Most of the remaining forest lies within the small (4.65
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