Justification This species has not been recorded since the type specimen was collected in 1866, and it was not found during recent surveys since 1998. Very little forest remains and habitat destruction has been extensive and is continuing. However, it cannot be assumed to be Extinct, because there have been some local reports, a thorough survey is required, and some Asian scops-owls survive even in secondary habitats. Any remaining population is likely to be tiny, and for these reasons it is treated as Critically Endangered.

Family/Sub-family Strigidae

Species name author (Schlegel, 1873)

Taxonomic source(s) Lambert and Rasmussen (1998)

Taxonomic note Otus magicus (Sibley and Monroe 1990, 1993) has been split into O. alfredi following Widodo et al. (1999), O. siaoensis following Lambert and Rasmussen (1998), O. enganensis following Andrew (1992), O. insularis and O. beccarii following Holt et al. (1999) and O. magicus (with species limits accordingly revised).

Identification 17 cm. Small, forest-dwelling owl. Typical scops-owl with relatively large head and feet, very and finely barred wings and tail. Similar spp. The only scops-owl on Siau. Voice Undocumented. Taxonomy Previously considered conspecific with Moluccan Scops-owl O. magicus, recent research has shown it to be a valid species on the basis of morphological features.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

<50

unset

120 km²

Yes

Range & population Otus siaoensis is only known from the holotype collected on the island of Siau, north of Sulawesi, Indonesia, in 1866. Given the small size of this island, and its generally unvegetated volcanic upper reaches, the original population was probably always modest in size, and any surviving population must be tiny, given that little forest remains. There is some suggestion that the species might survive on the basis of accounts given by local people; however, a recent survey of nocturnal birds in northern Sulawesi spent 32 days on Siau Island and failed to confirm that the species still occurs on the island, but semi-structured interviews revealed that small owls do occur and one unidentified call was heard; these reports remain unconfirmed¹, but a recent sound recording possibly relates to this species, and further searches are planned².

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: There are no ecological data, although it is reasonable to assume that the species was a forest dweller in common with its close congeners.

Threats Siau is currently experiencing rapid deforestation. In 1995, there was some lowland forest around Lake Kepetta in the south of the island, but this had been felled by 1998. In August 1998, the island was judged to have been largely converted to mixed plantation and scrub, but small patches of low trees survived. In October 1998, a five-day survey determined that only 50 ha of forest remained, all above 800 m on Gunung Tamata, in the centre of the island.

Conservation measures underway CITES Appendix II. In October 1998, five days were spent on the island of Tagulandang, just south of and almost as large as Siau, but only a few hectares of forest were found to remain, all above 600 m. The Wildlife Conservation Society is providing financial and technical support to the North Sulawesi local NGO 'PALS' to conduct extensive surveys of Siau Island to locate the species. If found, immediate conservation measures will be implemented².

Conservation measures proposed Survey the remaining forest on Siau and Tagulandang at different times of year, investigating any patch of trees, however remote the possibility of success may seem. In the event of its survival, initiate conservation measures at the site of rediscovery.

References BirdLife International (2001). 1. Hunowi (2006). 2. N. Brickle in litt. (2007, 2008).

Further web sources of information

Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International), Joe Tobias (BirdLife International)

Contributors Nicholas Brickle (Wildlife Conservation Society)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Otus siaoensis. Downloaded from http://www.birdlife.org on 9/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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