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Blue-wattled Bulbul Pycnonotus nieuwenhuisii
BirdLife is updating this factsheet for the 2016 Red List
Please email us with any relevant information

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

Taxonomic note
Pycnonotus nieuwenhuisii was not recognised in BirdLife International (2000, 2001) owing to an understanding that conclusive evidence was being produced of its hybrid origin. However, this evidence, published in Williams (2002) fails to elucidate how its distinctive (and consistent) plumage could realistically be derived from the purported parents or other species of Pycnonotus within its geographic range. Therefore, taking a precautionary approach the BirdLife Taxonomic Working Group continue to recognise nieuwenhuisii as a valid species although the need for further field and molecular work is acknowledged.

Distribution and population
Pycnonotus nieuwenhuisii is known from north-east Kalimantan (one specimen collected at 600 m in 1900) and Sumatra (one specimen collected at 700 m in 1937), Indonesia, and Brunei, where single birds were seen on five occasions in 1992 in Batu Apoi National Park (Collar et al. 1994). It is unusual for a species of bulbul to be widespread but to occur at such low densities, so this form may represent an extremely rare morph of another species or else hybrids, although it could be a genuinely rare habitat specialist that is occasionally forced to search other areas for food (Williams 2002).

Population justification
The global population size has not been quantified, but the species is described as extremely rare (del Hoyo et al. 2005).

Trend justification
The population is suspected to be stable in the absence of evidence for any declines or substantial threats.

The Sumatran specimen was collected in secondary scrub in pasture land, while the 1992 Brunei sightings occurred in lowland dipterocarp forest at c.60 m.

It is unknown whether the species is currently affected by any threats, but it is potentially threatened by habitat loss.

Conservation Actions Underway
No targeted conservation actions are known for this species. Conservation Actions Proposed
Carry out a genetic study of the two specimens and examine specimens of other Pycnonotus to help clarify taxonomic status (Williams 2002).

Collar, N. J.; Crosby, M. J.; Stattersfield, A. J. 1994. Birds to watch 2: the world list of threatened birds. BirdLife International, Cambridge, U.K.

del Hoyo, J.; Elliott, A.; Christie, D. 2005. Handbook of the Birds of the World, vol. 10: Cuckoo-shrikes to Thrushes. Lynx Edicions, Barcelona, Spain.

Williams, R. S. R. 2002. The rediscovery and doubtful validity of the Blue-wattled Bulbul Pycnonotus nieuwenhuisii. Forktail: 107-109.

Further web sources of information
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., Symes, A., Taylor, J.

Duckworth, W., Williams, R.

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

Recommended citation
BirdLife International (2016) Species factsheet: Pycnonotus nieuwenhuisii. Downloaded from on 25/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 25/10/2016.

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.

Key facts
Current IUCN Red List category Data Deficient
Family Pycnonotidae (Bulbuls)
Species name author (Finsch, 1901)
Population size Unknown mature individuals
Population trend Stable
Distribution size (breeding/resident) 56,600 km2
Country endemic? No
Links to further information
- Additional Information on this species