Sunda nightjar (Caprimulgus concretus)

Also known as: Bonaparte’s nightjar
GenusCaprimulgus (1)
SizeLength: 21 – 22 cm (2)

Classified as Vulnerable (VU) on the IUCN Red List (1).

Due to its cryptically patterned plumage, this large-eyed, curious-looking bird is often overlooked by birdwatchers and scientists alike. It belongs to the Caprimulgidae family, a name that in Latin translates as ‘goat sucker’ due to the ancient mythical belief that nightjars suckled milk from livestock. The scientific name concretus, meaning ‘stiff’ or ‘hard’, possibly owes to the Sunda nightjar’s ability to maintain a rigid posture when threatened (3).

The Sunda nightjar has brown upperparts that are spotted with chestnut, and brown underparts barred with chestnut, turning beige with brown bars on the belly and sides. It has brown wings, spotted with chestnut and cinnamon, a large, white patch on the throat, and a white, moustache-like stripe above the bill. The two outermost tail feathers of the male are tipped with white; only occasionally do these feathers on the female have white tips (2). The male’s song is a low, mournful 'wa-ouuuu' the second note descending in pitch. It sings from its perch mainly at dusk and dawn, but also on moonlit nights (2).

The Sunda nightjar occurs on the islands of Sumatra and Belitung (Indonesia), and Borneo (Indoensia, Brunei and Malaysia). Its apparent patchy distribution is not thought to be a result of genuine rarity but, instead, due to how easily the species is overlooked (2).

The Sunda nightjar is restricted mainly to lowland forest (2), including dipterocarp forest and heath forest (3). It usually occurs below 500 metres (3), although there is a record of this bird occurring at 900 metres (2).

The diet of the Sunda nightjar is poorly studied; however, the majority of other nightjar species feed on insects and this is presumed to hold true for the Sunda nightjar (3). Information on its foraging methods is also scarce, but it is known to often hunt over rivers, catching insects in short flights from its perch (3).

There is no known information on the Sunda nightjar’s breeding behaviour, although one egg has been collected from a nest on the ground in forest scrub, supporting the assumption that it is ground-nesting as is common throughout the genus (2).

As with all exclusively lowland birds in the Sundaic region, it is thought the Sunda nightjar’s population is in rapid decline due to extensive forest loss. An estimated 0.6 to 0.7 million hectares of lowland forest have been lost each year since 1985 to deforestation alone (4). Even so-called protected areas are threatened by logging, as dipterocarp trees are popular in the timber trade (2) (5).

In addition, major fires in the late 1990s affected an estimated 50,000 square kilometres of forest on Sumatra and Borneo. This damaged a large number of Indonesian parks and reserves and caused a dramatic reduction in biodiversity through the desiccation of the surrounding forest (6).

The species is found in protected areas in Sumatra and Borneo, including Way Kambas National Park (Sumatra) and Gunung Niut Nature Reserve (Borneo) (2) (6), and it is likely that further surveys would uncover populations in other protected areas (6).

There is an urgent requirement for studies to be conducted throughout the Sunda nightjar’s range on its population density and biology, which will help inform future conservation measures (2). This is needed not only for the Sunda nightjar but for all exclusively lowland species in the Sundaic region (2). A reduction of logging in lowland areas would also have enormous benefit to the region’s biodiversity (6).

To learn more about conservation in the Sundaic region see:

 To learn more about forest conservation see:

For more information on this and other bird species please see:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (May, 2010)
  2. Collar, N.J., Andreev, A.V., Chan, S., Crosby, M.J., Subramanya, S. and Tobias, J.A. (2001) Threatened Birds of Asia: The BirdLife International Red Data Book. BirdLife International, Cambridge, UK.
  3. del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the Birds of the World. Volume 5: Barn-owls to Hummingbirds. Lynx Edicions, Barcelona.
  4. Holmes, D., Rombang, W. M. and Octaviani, D. (2001) Daerah Penting Bagi Burung Kalimantan. PKA/BirdLife International–Indonesia Programme, Bogor, Indonesia.
  5. Maury-Lechon, G. and Curtet, L. (1998) Biogeography and evolutionary systematics of Dipterocarpaceae. In: Appanah, S. and Turnbull, J.M. (Eds.) A Review of Dipterocarps: Taxonomy, Ecology and Silviculture. Center for International Forestry Research, Bogor, Indonesia.
  6. BirdLife International (May, 2010)