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Large-billed Blue-flycatcher Cyornis caerulatus
BirdLife is updating this factsheet for the 2016 Red List
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This species qualifies as Vulnerable because it is suspected to be undergoing a rapid population decline as it is restricted to low-lying forest in a region where this habitat-type is being cleared and degraded at a rapid rate.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Niltava caerulata Collar and Andrew (1988)

14 cm. Small, brightly-coloured, forest-dwelling flycatcher. Male has dark blue upperparts, wings and tail, paler and brighter on the forehead and supercilium. Black chin, rest of underparts rusty-rufous. Female is brown above with pale eye-ring and blue rump and tail. Similar spp. Male Mangrove Blue-flycatcher C. rufigastra is similar, but lacks the contrasting pale forehead and supercilium and is duller on the lower back and rump. Female is blue above with whitish loral spot. Voice Thin three-note whistled song with last note descending, si-si-tiuuuw.

Distribution and population
Cyornis caerulata occurs on Borneo (including Brunei, Sabah and Sarawak, Malaysia, and Kalimantan, Indonesia) and Sumatra, Indonesia, where it is resident in humid lowland evergreen forest, ascending foothills locally to mid-altitudes. It appears to be rather patchily distributed, occurring at relatively low densities and generally uncommon.

Population justification
The population size is preliminarily estimated to fall into the band 10,000-19,999 individuals. This equates to 6,667-13,333 mature individuals, rounded here to 6,000-15,000 mature individuals.

Trend justification
A rapid and on-going population decline is suspected to be occurring, given that this species is restricted to lowland primary rainforest - a habitat that is being cleared at an alarming rate across the entire range.

It frequents the middle and understoreys of primary, selectively logged and mature secondary dryland rainforest, tending to occur in more dense or tangled areas or at edges of clearings. Although the species has been found to tolerate selectively logged and secondary rainforest, it occurs at much lower densities in these habitats (Ansell et al. 2010, Derhé 2010, Hua et al. 2011). It is often replaced in riverine forest by Malaysian Blue-flycatcher C. turcosa.

The species has been reported to occur at lower population densities in secondary and selectively forests than in primary forests (Ansell et al. 2010, Derhé 2010, Hua et al. 2011). Given its preference for primary lowland forest and restriction to Sumatra and Borneo, it is likely to be in steep decline from habitat loss, primarily through agricultural conversion following industrial-scale logging (even in some protected areas). Kalimantan lost just under 25% of its 1985 lowland forest cover in the subsequent 12 years, resulting in the prediction that this habitat-type could be eradicated from the entire province by 2010 if changes in policy and management were not forthcoming. Rates of loss on Sumatra were even higher, with 30% of lowland forest loss in the same 12-year period. Fire is also a threat to the species's habitat, with the major fires of 1997-1998 affecting 50,000 km2 of forest on Sumatra and Borneo and damaging at least 17 of Indonesia's parks and reserves. Following previous major conflagrations in 1972 and 1982-1983, the 1997-1998 fires accelerated the desiccation of the forest environment, halting regrowth and rendering unburnt adjacent areas ever more vulnerable to fire and ever poorer in biodiversity.

Conservation Actions Underway
It occurs in various protected areas throughout its range, including Sepilok Forest Reserve (Sabah), Gunung Mulu National Park (Sarawak), Kutai National Park (Kalimantan), Kerinci-Seblat and Way Kambas National Parks (Sumatra).Conservation Actions Proposed
Conduct surveys to investigate its population size and trends, ecological requirements and determine whether any specific conservation measures are needed. Provide support for the conservation and management of lowland protected areas in Sumatra and Borneo. Lobby for reduced logging of lowland forest in the Sundaic region.

Ansell, F. F., Edwards, D. P., Hamer, K. C. 2011. Rehabilitation of Logged Rain Forests: Avifaunal Composition, Habitat Structure, and Implications for Biodiversity-Friendly REDD+. Biotropica 43(504-511).

BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

Derhé, M. A. 2010. The effects of selective logging practices on understory birds in Bornean lowland dipterocarp forest. School of Biological Sciences, University of East Anglia.

Hua,F., Marthy, W., Lee, D., Nazri Janra, M. 2011. Globally threatened Sunda Blue Flycatcher Cyornis caerulatus: synthesis of global records and recent records from Sumatra. Forktail 27: 83-85.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Derhé, M., Gilroy, J.

Brickle, N., Poulsen, M.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Cyornis caerulatus. Downloaded from on 24/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 24/10/2016.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Large-billed blue-flycatcher (Cyornis caerulatus) 0

Key facts
Current IUCN Red List category Vulnerable
Family Muscicapidae (Chats and Old World flycatchers)
Species name author (Bonaparte, 1857)
Population size 6000-15000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 963,000 km2
Country endemic? No
Links to further information
- Additional Information on this species