Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Strigiformes Strigidae

Scientific Name: Otus gurneyi
Species Authority: (Tweeddale, 1879)
Common Name(s):
English Giant Scops-owl, Lesser Eagle-Owl, Giant Scops Owl
Spanish Autillo de Guerney, Búho de Mindanao
Mimizuku gurneyi (Tweeddale, 1879)
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.
Taxonomic Notes: Mimizuku gurneyi has been transferred to the genus Otus on the basis of the evidence presented in Miranda et al. (2011).
Identification information: 30 cm. Medium-sized owl with well-developed ear-tufts. Dark eyes. Rufescent facial disc outlined in black, conspicuous white eyebrows. Rufescent-brown crown and upperparts with darker shaft streaks, barred flight feathers and pale line on scapulars. Whitish underparts, washed rufous with bold black streaks. Similar spp. Larger than all sympatric Otus species, all of which lack such bold underpart streaking. Voice Loud wuaah repeated every 10-20 seconds in series of 5-10 calls.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2c+3c+4c;C2a(i) ver 3.1
Year Published: 2013
Date Assessed: 2013-11-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S.
Contributor(s): Collar, N.
Facilitator/Compiler(s): Benstead, P., Bird, J., Davidson, P., Derhé, M., Lowen, J., Peet, N.
This owl has a small population which is undergoing a rapid decline and severe fragmentation as a result of extensive deforestation. It therefore qualifies as Vulnerable.

Previously published Red List assessments:
2012 Vulnerable (VU)
2008 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Endangered (EN)
1994 Endangered (EN)
1988 Near Threatened (NT)

Geographic Range [top]

Range Description: Otus gurneyi is endemic to the Philippines, where it is known from Dinagat, Siargao and Mindanao. It has a relatively widespread distribution on Mindanao, where it has been discovered at eight new sites since 1990. However, its status is uncertain and, although it is likely to be under-recorded, it is considered to be probably uncommon at best.

Countries occurrence:
Continuing decline in area of occupancy (AOO): Yes
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 95600
Continuing decline in extent of occurrence (EOO): Yes
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 11-100
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 670
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population size is preliminarily estimated to fall into the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend Justification:  Dinagat has been almost totally deforested and rates of deforestation on Samar and Mindanao have been rapid, with virtually all remaining forest leased to logging or mining concessions. Hence, the species is suspected to be declining rapidly.
Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 2500-9999 Continuing decline of mature individuals: Yes
Extreme fluctuations: No Population severely fragmented: Yes
No. of subpopulations: 2-100 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: It inhabits primary, secondary and selectively logged dipterocarp forests, primarily in the lowlands up to 670 m, with occasional records up to 1,300 m, including in mossy forest.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 6.7
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): Its entire range has suffered extensive lowland deforestation. In 1988, forest cover had been reduced to an estimated 29% on Mindanao and in 1992 no more than 724 km2 of closed-canopy forest remained on Samar. These figures are likely to be overestimates, with most remaining lowland forest tracts leased to logging concessions and mining applications. Dinagat has been almost entirely deforested as a result of illegal logging and chromite surface-mining.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CITES Appendix I and II. It occurs in several protected areas, including Mt Apo and Mt Kitanglad Natural Parks and Siargao Island. There are older records from Mt Hilong-hilong Watershed Reserve and Mt Matutum Forest Reserve, which has been proposed as a national park. In the 1990s, it featured on a bilingual environmental awareness poster in the "Only in the Philippines" series.

Conservation Actions Proposed
Conduct nocturnal surveys, using voice playback, to establish presence/absence in poorly surveyed areas of Mindanao (e.g. Mts Three Kings, Diwata and Dapiak) and Samar. Conduct more intensive fieldwork to assess abundance, elevational range and habitat requirements at key sites. Promote improved protection of remaining forest at the sites listed above and campaign for a protected area in south Mindanao to encompass the cluster of sites with recent records.

Citation: BirdLife International. 2013. Otus gurneyi. The IUCN Red List of Threatened Species 2013: e.T22688911A50402686. . Downloaded on 10 October 2015.
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