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Greater racket-tailed Drongo

 

The greater racket-tailed drongo (Dicrurus paradiseus) is a medium-sized Asian bird which is distinctive in having elongated outer tail feathers with webbing restricted to the tips. They are placed along with other drongos in the family Dicruridae. They are conspicuous in the forest habitats often perching in the open and by attracting attention with a wide range of loud calls that include perfect imitations of many other birds. One hypothesis suggested is that these vocal imitations may help in the formation of mixed-species foraging flocks, a feature seen in forest bird communities where many insect feeders forage together. These drongos will sometimes steal insect prey caught or disturbed by other foragers in the flock and another ideas is that vocal mimicry helps them in diverting the attention of smaller birds to aid their piracy. They are diurnal but are active well before dawn and late at dusk. Owing to their widespread distribution and distinctive regional variation, they have become iconic examples of speciation by isolation and genetic drift.

 

The greater racket-tailed drongo was described by the Swedish naturalist Carl Linnaeus in 1766 in the twelfth edition of his Systema Naturae under the binomial name Cuculus paradiseus. It was one of 240 bird species that Linnaeus added to his twelfth edition based on the 1760 work Ornithologie by the French naturalist Mathurin Jacques Brisson. The current genus Dicrurus was introduced by the French ornithologist Louis Pierre Vieillot in 1816.

 

There are 13 recognised subspecies:

 

D. p. grandis (Gould, 1836) – north India through west and north Myanmar and south China to north Indochina

D. p. rangoonensis (Gould, 1836) – central India through Bangladesh, central Myanmar and north Thailand to central Indochina

D. p. paradiseus (Linnaeus, 1766) – south India to south Thailand, north Malay Peninsula and south Indochina

D. p. johni (Hartert, 1902) – Hainan Island (off southeast China)

D. p. ceylonicus Vaurie, 1949 – Sri Lanka

D. p. otiosus (Richmond, 1902) – Andaman Islands

D. p. nicobariensis (Baker, ECS, 1918) – Nicobar Islands

D. p. hypoballus (Oberholser, 1926) – central Malay Peninsula

D. p. platurus Vieillot, 1817 – south Malay Peninsula, Sumatra and nearby islands

D. p. microlophus (Oberholser, 1917 – islands in the South China Sea (Tioman Island, Anambas Islands and the North Natuna Islands)

D. p. brachyphorus (Bonaparte, 1850) – Borneo

D. p. banguey (Chasen & Kloss, 1929) – islands off north Borneo

D. p. formosus (Cabanis, 1851) – Java

 

In most of its range in Asia, this is the largest of the drongo species and is readily identifiable by the distinctive tail rackets and the crest of curled feather that begin in front of the face above the beak and along the crown to varying extents according to the subspecies. The tail with twirled rackets is distinctive and in flight it can appear as if two large bees were chasing a black bird. In the eastern Himalayas the species can be confused with the lesser racket-tailed drongo, however the latter has flat rackets with the crest nearly absent.

 

This widespread species includes populations that have distinct variations and several subspecies have been named. The nominate form is found in southern India, mainly in forested areas of the Western Ghats and the adjoining hill forests of peninsular India. The subspecies in Sri Lanka is ceylonicus and is similar to the nominate form but slightly smaller. The subspecies found along the Himalayas is grandis and is the largest and has long glossy neck hackles. The Andaman Islands form otiosus has shorter neck hackles and the crest is highly reduced while the Nicobars Island form nicobariensis has a longer frontal crest and with smaller neck hackles than otiosus. The Sri Lanka drongo (D. lophorinus) used to be treated as a subspecies as it was believed to form hybrids with ceylonicus but is now considered a separate species on the basis of their overlapping ranges. Specimens of the nominate form have sometimes been confused with the Sri Lanka drongo. Considerable variation in shape of the bill, extent of the crest, hackles and tail rackets exists in the island populations of Southeast Asia. The Bornean brachyphorus (=insularis), banguey of Banggai lack crests (banguey has frontal feathers that arch forwards) while very reduced crests are found in microlophus (=endomychus; Natunas, Anambas and Tiomans) and platurus (Sumatra). A number of forms are known along the Southeast Asian islands and mainland including formosus (Java), hypoballus (Thailand), rangoonensis (northern Burma, central Indian populations were earlier included in this) and johni (Hainan).

 

Young birds are duller, and can lack a crest while moulting birds can lack the elongate tail streamers. The racket is formed by the inner web of the vane but appears to be on the outer web since the rachis has a twist just above the spatula.

 

The distribution range of this species extends from the western Himalayas to the eastern Himalayas and Mishmi Hills in the foothills below 1,200 m (3,900 ft). They are found in the hills of peninsular India and the Western Ghats. Continuing into the west to the islands of Borneo and Java in the east through the mainland and islands.

 

They common whistle note that is made leads to its local name in many parts of India of kothwal (which means a "policeman" or "guard", who used a whistle that produced a similar note), a name also applied to the black drongo and in other places as the Bhimraj or Bhringaraj. In Mizo language of northeast India, it is called Vakul and the Mizo people regarded the bird as ' 'king of the birds' ' Prior to the 1950s it was often kept in captivity by people in parts of India. It was said to be very hardy and like a crow, accommodating a varied diet. Edward H. Schafer considered the greater racket-tailed drongo as the basis for the divine kalaviṅka birds mentioned in Chinese and Japanese Buddhist texts.

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