Data Zone
Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is suspected to be declining but the rate has not been quantified and hence the species cannot be assessed against the population trend criterion. The population size has not been quantified globally but does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size has not been quantified, but the species is described as widespread and generally common (del Hoyo et al. 1999). Based on the density estimated from a tracking study of four breeding birds over four years in Canberra (1.7 birds/km2; Olsen et al. 2011), N. b. boobook is estimated to number 100,000 (80,000-160,000) mature individuals and N. b. ocellata 265,000 mature individuals (220,000-440,000) (Loyn et al. 2021). The population sizes of the remaining subspecies have not been estimated.
Trend justification
BirdLife Australia (2015) reported that the Southern Boobook (including both N. b. boobook and N. b. ocellata) had declined throughout most of the 15-year period from 1999 to 2013. Despite high variability year to year, by 2013, boobooks had decreased to low levels, with average reporting rates of only between 1–3%. They were declining across all but one of the six regions they inhabit in Australia, with trends in the Eastern Mallee assessed as either stable or highly variable. Olsen and Trost (2015) found one breeding pair of N. b. boobook in an area near Canberra that had supported, on average, about nine breeding pairs since 1993. Reporting rates from Birdata (BirdLife Australia 2020) analysed for both subspecies and covering a 15-year period (three generations, 2003–2018) showed inconsistent trends: N. b. ocellata declined by 57% and 76% for 2 ha 20 min surveys and 500 m radius area searches, respectively; N. b. boobook declined by 17% and 54% for 2 ha 20 min surveys and 500 m radius area searches, respectively. Composite trend analysis for both subspecies and survey methods indicated a 64% decline over 15 years (three generations). Reporting rates were low (<6%) in all surveys, however, and these results need to be interpreted with caution (Loyn et al. 2021). The surveys used methods that were not targeted at detecting nocturnal species and many survey sites were located in urban and peri-urban locations where Southern Boobooks were likely to show a decreasing density as levels of urbanisation increase (Weaving et al. 2011). There are no data on trends for the remaining subspecies, however forest loss is ongoing throughout the global range (Global Forest Watch 2023 using data from Hansen et al. [2013] and methods disclosed therein) which may be causing declines through the loss of hollow-bearing trees. Overall, the population is suspected to be declining but the rate has not been quantified.
The species comprises seven subspecies in Indonesia, Papua New Guinea and Australia: N. b. moae and cinnamomina on the Lesser Sundas, remigalis on the Kai Islands, pusilla on southern New Guinea, and ocellata, boobook and lurida occurring across much of Australia.
Individuals occur in a wide variety of habitats, from forests, woodlands, farmlands, orchards and suburban gardens to sparsely treed semi-arid scrub and borders of treeless plains (Weaving et al. 2011, Fulton et al. 2020). They roost by day in thick foliage or tree hollows, rarely in caves, singly, or in pairs or family groups and feed on insects, small mammals and other small animal species. They usually nest in tree hollows and lay 2–3 eggs (Higgins 1999).
Few threats have been identified. Anticoagulant rodenticides, some of which are recommended for control of rodents in and around buildings (industrial and household, APVMA 2020) have been found prevalent in Southern Boobooks in Australia (Lohr 2018, Lohr and Davis 2018) and may have significantly reduced numbers in urban and peri-urban areas. The populations most likely to be affected by rodenticides may also be reflected in a geographical bias in where birdwatchers look for birds and could explain some of the trend in reporting rate, but this needs confirmation (Loyn et al. 2021). Another potential threat is competition with European honey bees Apis mellifera for nesting hollows, identified as a threat for other owls (Kavanagh and Stanton 2009). Loss of hollow-bearing trees is an issue in forests managed for timber or subjected to increasing fire frequency (Loyn et al. 2004), and in other areas (Lohr 2019), but is less likely to be such an issue in remote parts of Australia.
Text account compilers
Vine, J.
Recommended citation
BirdLife International (2024) Species factsheet: Southern Boobook Ninox boobook. Downloaded from
https://datazone.birdlife.org/species/factsheet/southern-boobook-ninox-boobook on 18/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 18/12/2024.