Ninox strenua 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Strigiformes Strigidae

Scientific Name: Ninox strenua
Species Authority: (Gould, 1838)
Common Name(s):
English Powerful Owl, Powerful Boobook
Spanish Nínox Robusto
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Harding, M., Ekstrom, J., Butchart, S.
This species has a very 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 appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be small, but it is not believed to 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.
Previously published Red List assessments:
2009 Least Concern (LC)
2008 Least Concern (LC)
2004 Least Concern (LC)
2000 Lower Risk/least concern (LR/lc)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: This species occurs in open forest and woodlands in eastern Australia, from south-west Victoria to at least Eungella, and possibly Bowen, Queensland. Large areas of the species' range are now unsuitable as a result of clearing for agriculture and pastoralism, although the species now occupies suburban Brisbane, Sydney and Melbourne.
Countries occurrence:
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 574000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 1500
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Garnett and Crowley (2000) estimated the population size as follows: fewer than 500 pairs (equating to 1,000 individuals) in Victoria, approximately 1,000-1,500 pairs in north-east New South Wales (approximately 2,000-3,000 individuals) and approximately 125 pairs (equating to 250 individuals) in south-east New South Wales. This gives an overall population estimate of between 3,250 and 4,250 individuals, equating roughly to 2,200-2,800 mature individuals.

Trend Justification:  Garnett and Crowley (2000) state that the current population is stable and broadly similar to pre-European population levels. The species is equally able to live and breed in heavily logged, lightly logged or unlogged forest.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 2200-2800 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Threats [top]

Major Threat(s): Although densities in remaining forest may eventually be affected by a reduction in the availability of suitable nest hollows and den sites as a result of intensive forestry practices, studies indicate birds persist in mosaics of unlogged forest, in which they nest, and logged forest, in which they forage. There was no difference in density between heavily logged, lightly logged and unlogged forest. Intense wildfire can result in local loss but, if suitable habitat remains nearby, they may return to forage. Poisoning, disturbance and predation by foxes may also cause nest failure and some mortality, but are unlikely to be significant (Garnett and Crowley 2000).

Citation: BirdLife International. 2012. Ninox strenua. The IUCN Red List of Threatened Species 2012: e.T22689389A40412102. . Downloaded on 26 November 2015.
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