White-winged nightjar (Eleothreptus candicans)

Description

White-winged nightjar fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

White-winged nightjar description

This unusual bird belongs to the Caprimulgidae family, a name which is derived from ‘goatsucker’ in Latin and was bestowed on these birds in the mistaken belief that their large, gaping mouths were used to suckle livestock. The white-winged nightjar has pale greyish-brown plumage on the upperparts, speckled, barred and streaked brown. The breast is similarly patterned, except tinged with chestnut, and the rest of the underparts are white on the male and brownish on the female. The crown is boldly spotted blackish and the face has a distinctive pale greyish stripe, which looks like a moustache. The male also differs from the female by its mostly white tail and white wings tipped with black, which are clearly visible in flight; the female lacks these white parts ⁽⁵⁾. The white-winged nightjar is a mostly silent bird, except for the strange mechanical noise produced by the male during displays ⁽⁶⁾.   

Synonyms

Caprimulgus candicans.

Size

Length: 19 - 21 cm ⁽²⁾

Male weight: 46 - 55 g ^{(3) (4)}

Female weight: 51 - 56 g ⁽⁴⁾

White-winged nightjar biology

Like other nightjars, the white-winged nightjar is active at dusk, dawn and throughout the night, when it flies over hillsides and hilltops hunting for food. It flies slowly, and frequently glides, one to two metres above the grass, searching for moths, beetles and flies. This nocturnal hunter can also be found perched on low plants, termite mounds or palms, where it will make sudden short sallies to snatch prey from the air ⁽²⁾.

During the breeding season, the white-winged nightjar male defends small display territories in open areas on the upper slopes of ridges, which usually contain one to three display areas. Each display area typically consists of a vertical perch and a low anthill, separated by a few metres, and is used by the male during moonlit nights to perform courtship displays. From the elevated perch, the male flies in a gentle arc with ‘butterfly-like’ wing beats and the wings held back. They alight briefly on top of the anthill before flying with strong wing beats back to the perch. During these displays, the male produces an unusual, mechanical grrrrt sound, thought to be produced by the wings ⁽⁶⁾.

Relatively little is known about breeding in the white-winged nightjar, as the first ‘nest’ was discovered as recently as 1997. There is no constructed nest as such; rather, the clutch of two eggs is laid directly on the ground, adjoining a small ‘clearing’, in grassland ⁽⁴⁾. In Paraguay, nesting occurs between September and December, with the female apparently carrying out all the incubation, brooding and chick provisioning duties on her own ⁽⁴⁾. 

White-winged nightjar range

The white-winged nightjar occurs in central South America where it is known from southern Brazil, eastern Paraguay and Bolivia. It has only been found at four localities since the 1980s: Emas National Park in Brazil, Beni Biological Station in Bolivia, and Mbaracayú Forest Nature Reserve and Laguna Blanca in Paraguay ^{(7) (8)}.

White-winged nightjar habitat

The white-winged nightjar inhabits open grasslands with scattered trees and bushes, shrubs or dwarf palms, and / or abundant anthills and termite mounds. It apparently shows a preference for grasslands regenerating after fires, and avoids areas of tall grass ⁽⁴⁾. The white-winged nightjar generally occurs between 170 and 1,000 metres above sea level ⁽⁷⁾. 

White-winged nightjar status

Classified as Endangered (EN) on the IUCN Red List ⁽¹⁾.

White-winged nightjar threats

Whilst the white-winged nightjar has a wide distribution, within the range there is little suitable habitat left due to the spread of agriculture, ranching and grass fires ^{(5) (8)}. Fires are usually started by landowners trying to clear their pasture and promote grass re-growth, and some spread uncontrolled into protected areas, while other fires are sadly started deliberately for malicious reasons within reserves ⁽⁹⁾.

The invasion and spread of non-native grass species also poses a potential threat to the white-winged nightjar. Although the impacts on this species are not fully understood, the spread of non-native grasses has been suggested to increase an area's susceptibility to fires, and the near-complete, dense ground cover they create probably also reduces the availability of the small 'clearings' that the white-winged nightjar seems to require for access to roost and nest sites ⁽⁹⁾.

White-winged nightjar conservation

The white-winged nightjar is protected by law in Brazil, and occurs in a few protected areas: Emas National Park, Mbaracayú Forest Nature Reserve and Beni Biological Station. However, active fire management is required in these areas as while occasional, small-scale fires create a mosaic of suitable vegetation, extensive, uncontrolled wildfires can be very destructive, particularly if they occur during the breeding season ⁽⁷⁾. 

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

For further information on this species see:

• BirdLife International:
  http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=2390&m=0

Authentication

Authenticated (02/09/10) by Dr Rob Pople.
http://www.zoo.cam.ac.uk/zoostaff/bbe/Pople/Rob1.htm

Glossary

Nocturnal

Active at night.

References

1. IUCN Red List (September, 2010)
   http://www.iucnredlist.org
2. Cleere, N. (1998) Nightjars: A Guide to Nightjars and Related Nightbirds. Pica Press, Robertsbridge. 
3. López Lanús, B., Clay, R.P. and Lowen, J.C. (1998) A new plumage of the white-winged nightjar Caprimulgus candicans (Aves: Caprimulgidae). Bulletin of the British Ornithologists' Club, 118(3): 183-187.
4. Pople, R.G. (2003) The Ecology and Conservation of the White-winged Nightjar Caprimulgus candicans. Ph.D. dissertation, University of Cambridge, UK. Available at:
   http://www.dspace.cam.ac.uk/handle/1810/225237.
5. 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. 
6. Clay, R.P., López Lanús, B., Tobias, J.A., Lowen, J.C. and Mazar Barnett, J. (2000) The display of the white-winged nightjar. Journal of Field Ornithology, 71(4): 619-626.
7. BirdLife International (September, 2010)
   http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=2390&m=0
8. Holyoak, D.T. (2001) Nightjars and their Allies: the Caprimulgiformes. Oxford University Press, Oxford.
9. Pople, R. (2010) Pers. comm.