[7][8] In 1912 Mathews[1][9] identified eight subspecies of masked owl in Australia, including T. n. castanops, T. n. kimberli, T. n. melvillensis, T. n. mackayi, T. n. novaehollandiae, T. n. perplexa, T. n. riordani and T. n. whitei, based on observations of distribution, morphology and plumage.

[13] The Action Plan for Australian Birds 2020 treats Tyto novaehollandiae kimberli as separate from the Cape York and wet tropics race T. n. galei, however the relationship between these subspecies requires further investigation.

[3] Several early historical specimens labelled from this region are held in museum collections but recent surveys in the Borroloola area and at Pungalina Station failed to detect northern masked owls.

[14] In 2019 and 2020 there were confirmed northern masked owl records from Groote Eylandt, north-eastern Arnhemland, Kakadu National Park and the Mitchell Plateau and Yampi Peninsula in Western Australia.

[15] Relatively high densities of northern masked owls have been detected on Groote Eylandt, with a home range estimate of 4–5 km2 based on sampling across several large forest grids covering approximately 5000 ha.

[4] Recently discovered roost sites in the Kimberley have all been associated with tall Melaleuca gallery (riparian) forest adjacent to sandstone escarpments and open savannah woodland.

[4] Stomach contents of two northern masked owl specimens from the Kimberley contained small birds and marsupials including savanna glider (Petaurus ariel).

There are a limited number of localities where the northern masked owl appears to remain relatively common, including Garig Gunak Barlu National Park, the north-west Kimberley and the Anindilyakwa Indigenous Protected Area (Groote Eylandt).

These sites are likely to represent important refuge areas for northern masked owl populations and have potentially been less impacted by fire regime changes, disturbance from pastoralism, feral animals and decline of prey species that has been documented at other locations.

[3] Identified and potential threats to populations of the northern masked owl are related to the direct and indirect actions of humans (Homo sapiens), including land clearing, altered fire regimes, stocking with exotic ruminants, proliferation of feral animals and weeds and atmospheric pollution leading to global heating.

However, these trees continue to be abundant[29] and highly mobile species with large home range areas such as northern masked owls may be less vulnerable to local impacts of fire on key habitat resources.

[3] The northern masked owl was ranked as having a medium level of sensitivity to the impacts of global heating in a study conducted by the Australian National Climate Change Adaptation Research Facility.

Northern masked owl occur in other Indigenous Protected Areas and Indigenous lands, including the Anindilyakwa, Arrabrkbi, Birriwinjku, Bunubu, Dambimangari, Gagudju, Garawa, Kundjeyhmi, Jawoyn, Kamu, Karde, Yek Diminin, Kenbi, Koonguruku, Labarganyan, Larrakia, Limilngan, Malak, Maranunggu, Mayala, Mirarr, Ngan'gi, Ngombur, Ngumbarl, Nimanburr, Rakpeppimenarti, Uunguu, Waanyi, Wagiman, Warai, Warrwa, Wilinggin, Wulna, Wunambal, Gaambera and Yammirr.