White-bellied drongo

The white-bellied drongo (Dicrurus caerulescens) is a species of drongo found across the Indian Subcontinent. Like other members of the family Dicruridae, they are insectivorous and mainly black in colour, but with a white belly and vent. Young birds are, however, all black and may be confused with the black drongo, which is smaller and more compact in appearance. The subspecies found in Sri Lanka has white restricted to the vent.

White-bellied drongo
Dicrurus caerulescens caerulescens from Ghatgarh, Uttarakhand, India

Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Dicruridae
Genus: Dicrurus
Species:
D. caerulescens
Binomial name
Dicrurus caerulescens
Subspecies

D. c. caerulescens
D. c. leucopygialis Blyth, 1846
D. c. insularis Sharpe, 1877

Synonyms
  • Lanius caerulescens Linnaeus, 1758
  • Balicassius caerulescens (Linnaeus, 1758)
  • Buchanga caerulescens (Linnaeus, 1758)

Description

This drongo is black without any glossy feathers on the upperside and greyish on the throat and breast, while the belly and vent are entirely white in the Indian form which is the nominate subspecies. The fork of the tail is less deep than in the black drongo which is often seen in the same habitats. Young black drongo's can have a lot of white on the underside but it is usually scaly in appearance. The Sri Lankan forms insularis of the northern dry zone and leucopygialis of the southern wet zone have the white restricted to the vent. Birds that are less than a year old lack the white on the underside but are browner above and greyish below.[2] Males have a very slightly shorter tail on average than females.[3]

Nominate subspecies (Sindhrot, Gujarat)

The size of the birds varies clinally with northern birds larger. The extent of white on the underside also declines with size although there is a lot of local variation. The Sri Lankan forms leucopygialis and insularis are darker than the Indian form and there is some intergradation within the Sri Lankan forms.[4][5][6] The species is believed to be closely related to Dicrurus leucophaeus[4] but has not be confirmed with molecular sequence studies.[7]

Both the white-bellied drongo and the black drongo share a diploid chromosome number of 68.[8]

Distribution and habitat

The white-bellied drongo is a resident breeder in India and Sri Lanka. This species is usually found in dry scrub or open forests. The distribution is restricted to peninsular India south of the Himalayas and to the west of the Gangetic delta bounded on the west by the Aravallis.[2][9]

Behaviour and ecology
D. c. leucopygialis (Colombo, Sri Lanka)

Birds are often seen singly or in groups of up to three individuals, sometimes joining mixed-species foraging flocks. They perch upright close to the tops of trees and capture insects in the air with short aerobatic sallies. Larger insects may be captured using their claws. The song of this drongo is a series of staccato notes interspersed with clear notes and may include mimicry of other bird calls.[2][10]

The breeding season is from February to July. The cup nest is similar to that of the black drongo but is usually made up of more twigs and is well lined with grass. Two to four eggs, pale salmon coloured with reddish blotches on the broad end, are laid in the nest which may be 20 to 30 feet high in the fork of a tree.[11][12] These are aggressive at the nest and will potential threats much larger than themselves.[13] When mobbing they have been observed to imitate the alarm calls of squirrels or the mewing of a cat[14] and is known to join to mixed-species foraging flocks.[15]

Although primarily insectivorous they are opportunistic and are known to prey on small birds.[16] Like other drongos, they use their feet while handling their prey.[17] They have been known to take insects attracted to artificial lights late at dusk.[18] They also visit large flowers for nectar, particularly Bombax, Erythrina[10] and may pollinate species such as Helicteres isora.[19] The bird louse Philopterus kalkalichi Ansari, 1955 whose type host is the black drongo has also been found on white-bellied drongos.[20]

References
  1. BirdLife International (2012). "Dicrurus caerulescens". IUCN Red List of Threatened Species. 2012. Retrieved 26 November 2013.CS1 maint: ref=harv (link)
  2. Rasmussen, PC & JC Anderton (2005). Birds of South Asia: The Ripley Guide. 2. Smithsonian Institution & Lynx Edicions. pp. 590–591.
  3. Balmford, Andrew; Jones, Ian L; Thomas, Adrian L. R (1994). "How to Compensate for Costly Sexually Selected Tails: The Origin of Sexually Dimorphic Wings in Long-Tailed Birds". Evolution. 48 (4): 1062. doi:10.1111/j.1558-5646.1994.tb05293.x. PMID 28564484.
  4. Vaurie, Charles (1949). "A revision of the bird family Dicruridae". Bulletin of the AMNH. 93 (4): 203–342. hdl:2246/1240.
  5. Tweeddale, A.; Marquis of (1878). "Notes on the Dicruridae, and on their Arrangement in the Catalogue of the Collection of the British Museum". Ibis. 4 (2): 69–84. doi:10.1111/j.1474-919X.1878.tb07028.x.
  6. Wait, WE (1922). "The Passerine birds of ceylon". Spolia Zeylanica. 12: 22–194.
  7. Pasquet, Eric; Jean-Marc Pons; Jerome Fuchs; Corinne Cruaud & Vincent Bretagnolle (2007). "Evolutionary history and biogeography of the drongos (Dicruridae), a tropical Old World clade of corvoid passerines" (PDF). Molecular Phylogenetics and Evolution. 45 (1): 158–167. doi:10.1016/j.ympev.2007.03.010. PMID 17468015.
  8. Bhunya, S. P; Sultana, T (1979). "Somatic Chromosome Complements of Four Passerine Birds and Their Karyological Relationship". Caryologia. 32 (3): 299. doi:10.1080/00087114.1979.10796794.
  9. Oates, EW (1889). Fauna of British India. Birds. Volume 1. Taylor and Francis, London. p. 316.
  10. Ali, S & SD Ripley (1986). Handbook of the Birds of India and Pakistan. Volume 5 (2nd ed.). Oxford University Press. pp. 122–124.
  11. Campbell, W Howard (1906). "Nesting of the white-bellied drongo (Dicrurus caerulescens)". J. Bombay Nat. Hist. Soc. 17 (1): 248.
  12. Hume, AO (1889). The nests and eggs of Indian Birds. Volume (1. Second ed.). R H Porter, London. p. 209.
  13. Green, EE (1909). "Pugnacity of the Drongo". Spolia Zeylanica. 6 (23): 130–131.
  14. Goodale, E & S W Kotagama (2006). "Context-dependent vocal mimicry in a passerine bird" (PDF). Proc. R. Soc. B. 273 (1588): 875–880. doi:10.1098/rspb.2005.3392. PMC 1560225. PMID 16618682.
  15. Ali, Salim (1996). The Book of Indian Birds. Twelfth edition. Oxford University Press. p. 228.
  16. Ali, Sálim (1951). "White-bellied Drongo catching a bird". J. Bombay Nat. Hist. Soc. 49 (4): 786.
  17. Clark, George A. Jr. (1973). "Holding Food with the Feet in Passerines". Bird-Banding. 44 (2): 91–99. doi:10.2307/4511942. JSTOR 4511942.
  18. Sharma, SK (2003). "Nocturnal feeding by White-bellied Drongo Dicrurus caerulescens". J. Bombay Nat. Hist. Soc. 100 (1): 144.
  19. Santharam, V. (1996). "Visitation patterns of birds and butterflies at a Helicteres isora Linn. (Sterculiaceae) clump" (PDF). Current Science. 70 (4): 316–319.
  20. Sychra, Oldrich; Palma, Ricardo L.; Saxena, Arun K.; Ahmad, Aftab; Bansal, Nayanci; Adam, Costică (2011). "Chewing lice of the genus Philopterus (Phthiraptera: Philopteridae) from drongos (Passeriformes: Dicruridae)". Zootaxa. 2868: 51–61.
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