NT
Biak Scops-owl Otus beccarii



Taxonomy

Taxonomic note
Otus magicus and O. tempestatis (del Hoyo and Collar 2014) were previously lumped as O. magicus, and O. alfredi, O. siaoensis, O. enganensis, O. insularis and O. beccarii (del Hoyo and Collar 2014) were split from O. magicus following Widodo et al. (1999), Lambert and Rasmussen (1998), Andrew (1992) and Holt et al. (1999). Prior to that all these taxa were lumped in O. magicus following Sibley and Monroe (1990, 1993).

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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Holt, D. W.; Berkley, R.; Deppe, C.; Enriquez Rocha, P. L.; Olsen, P. D.; Petersen, J. L.; Rangel Salazar, J. L.; Segars, K. P.; Wood, K. L. 1999. Strigidae (typical owls). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 76-242. Lynx Edicions, Barcelona, Spain.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2023 Near Threatened B1b(iii)
2016 Vulnerable B1ab(ii,iii,v); C2a(ii)
2014 Vulnerable B1ab(ii,iii,v); C2a(ii)
2012 Endangered B1ab(ii,iii,v)
2008 Endangered B1a+b(ii,iii,v)
2004 Endangered
2000 Endangered
1994 Not Evaluated
1988 Near Threatened
Species attributes

Migratory status not a migrant Forest dependency high
Land-mass type Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 3,600 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 15000-45000, 15000-20000 mature individuals poor suspected 2022
Population trend decreasing poor suspected 2016-2026
Rate of change over the past 10 years/3 generations (longer of the two periods) 1-9% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 1-9% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 1-9% - - -
Generation length 3.04 years - - -
Number of subpopulations 1 - - -
Percentage of mature individuals in largest subpopulation 100% - - -

Population justification: The population size of this species has not previously been directly quantified. The densities of other Otus species is also surprisingly poorly known. Otus rufescens occurs at densities of c. 20 birds/km2 in Sarawak (Fogden 1976), but the applicability of those data to the present species is wholly unknown. Using the global landcover 2 estimate of forest cover for the island (closed to open broadleaved evergreen or semi-deciduous forest) and excluding fragments smaller than 1 km2 results in an area classified as forest habitat of 1,572 km2. If a density of 10-30 birds/km2 is applied to this area (a range centred on the density of O. rufescens, but acknowledging uncertainty on the appropriateness of this), a population size of c.15,000-45,000 mature individuals is yielded. Qualitative descriptions of the species' abundance of the species vary from 'fairly common and widespread' (Beehler and Pratt 2016) to 'rare' (Gregory 2017), while eBird data suggest it is indeed widespread, but is rarely encountered in large numbers. The lower bound of this estimate (15,000-20,000 mature individuals) is precautionarily considered the best, although this requires confirmation.

Trend justification: No direct assessment of rate of population change has been made for the species. It is considered to be forest dependent and there has been a slow rate of forest cover loss, up to 4% in the ten years to 2022 (data from Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein) and this is suspected to be causing broadly equivalent reductions in population size of this species. These rates are suspected to occur in the future. An accelerated rate of decline is considered unlikely given the impenetrability of Supiori's forests.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Indonesia extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Swamp major resident
Altitude 0 - 1000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2024) Species factsheet: Otus beccarii. Downloaded from https://datazone.birdlife.org/species/factsheet/biak-scops-owl-otus-beccarii on 26/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 26/02/2024.