Document ID: chunk:federal_register_of_legislation:F2025L00287:reg:3:p140
Version: federal_register_of_legislation:F2025L00287
Segment Type: reg
Provision Reference: reg 3 (pt 140/276)
Character Range: 545879–548596

(TSSC 2016b).

Distribution and abundance
The Norfolk Island morepork (or boobook owl) was first recorded by King in 1788–90. Since 1909 the owl had been recorded as occurring largely in the gullies surrounding Mt Pitt (Smithers & Disney 1969; Olsen et al. 1989). A reasonable population remained in 1912–13 but by 1968 the owl was considered extremely rare and was heard only occasionally (Turner et al. 1968; Smithers & Disney 1969). By 1986 the population had declined to a single female, and the genetically pure form of the species is now extinct (TSSC 2016b).
Two males from the closely related New Zealand subspecies were introduced in 1987. In 1989 the Norfolk female and one of the New Zealand males raised their first chicks. They also produced chicks in 1990 but those were the last chicks produced by the Norfolk female, and she was last recorded in October 1995. There has been subsequent second and third generation breeding with 45 'hybrid' offspring banded up to December 2007. The current population is entirely descended from that single breeding pair: the last female Norfolk Island morepork Ninox n. undulata and one of the introduced males N. n. novaeseelandiae (Olsen et al. 1989).
Successful breeding was observed in every year from 1993 to 2007. Subsequently, a single successful breeding event was observed between 2008 and 2018 (successful breeding in 2011 only). In 2016, there were estimated to be 32 individuals (Wilson 2016); estimates from more recent surveys reported a population of 20–30 (Sperring et al. 2021a). After the establishment of new nest boxes, one nest found in 2019 produced two fledglings, while a single nest found in 2020 (believed to be from the same pair and in a box near the location of the successful nest in 2019) had eggs that did not hatch (Sperring et al. 2021b). Although surveys in 2019–2021 detected just two previously banded birds of the 12 captured, indicating that undetected breeding has occurred at some point, the population possibly consists of ageing birds that are not reproducing at a sufficient rate to maintain the population. In December 2023, a nest with two new chicks was discovered and was being monitored.
The population is now fairly evenly distributed across the entire national park with a higher density on the southern slopes of Mt Pitt and Mt Bates. Tracking data from spring 2019 and 2020 showed that the average territory size for owls living mostly within the national park was 48 hectares while the average size for owls outside of the park was 128 hectares. Territory sizes during winter are similar to those in spring, though one owl tracked during winter, and displaying behaviour suggestive of searching for a mate, ranged