Greater Racket-tailed Drongo
Encyclopedia
The Greater Racket-tailed Drongo, Dicrurus paradiseus, is a medium-sized Asia
n bird
which is distinctive in having elongated outer tail feathers with webbing restricted to the tips. They are placed along with other drongo
s 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. It has been suggested that these 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. 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
.
, 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 Lankan form lophorinus used to be treated as a subspecies due to the suggestion that it formed hybrids with ceylonicus is considered a separate species in newer taxonomic treatments on the basis of their overlapping ranges. Specimens of the nominate form have sometimes been confused with lophorinus. 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.
Their calls are extremely varied and include monotonously repeated whistles, metallic and nasal sounds as well as more complex notes and imitations of other birds. They begin calling from as early as 4 am in moonlight often with a metallic tunk-tunk-tunk series. They have an ability to accurately mimic alarm call
s of other birds that are learnt through interactions in mixed-species flocks. This is quite unusual, as avian vocal mimicry has hitherto been believed to be ignorant of the original context of the imitated vocalization. African Grey Parrot
s are known to use imitated human speech in correct context, but do not show this behavior in nature. This drongo's context-sensitive use of other species' alarm calls is thus analogous to a human learning useful short phrases and exclamations in a number of foreign languages. A special alarm note is raised in the presence of Shikra
s that has been transcribed as a loud kwei-kwei-kwei...shee-cuckoo-sheecuckoo-sheecuckoo-why!. They have been said to imitate raptor calls so as to alarm other birds and steal prey from them in the ensuing panic. They are also known to imitate the calls of species (known sometimes even to fluff up and moving head and body like a Jungle Babbler) that typically are members of mixed-species flocks such as babblers and it has been suggested that this has a role in the formation of mixed-species flocks. In some places they have been found to be kleptoparasitic
on others in mixed-species flock, particularly Laughingthrushes but they are most often involved in mutualistic and commensal relations. Several observers have found this drongo associating with foraging woodpeckers and there is a report of one following a troop of macaques.
The Greater Racket-tailed Drongo is a resident breeder throughout its range. The breeding season in India is April to August. Their courtship display may involve hops and turns on branches with play behaviour involving dropping an object and picking it in mid air. Their cup nest is built in the fork of a tree and the usual clutch is three to four egg
s. The eggs are creamy white with blotches of reddish brown which are more dense on the broad end.
and in other places as the Bhimraj or Bhringaraj. 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. The great racket tailed drongo is considered as a good omen as opposed to the related species black drongo which is considered as a bad omen.
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
which is distinctive in having elongated outer tail feathers with webbing restricted to the tips. They are placed along with other drongo
Drongo
The drongos are a family of small passerine birds of the Old World tropics, the Dicruridae. This family was sometimes much enlarged to include a number of largely Australasian groups, such as the Australasian fantails, monarchs and paradise flycatchers...
s 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. It has been suggested that these 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. 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
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
by isolation and genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
.
Description
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 DrongoLesser Racket-tailed Drongo
The Lesser Racket-tailed Drongo is a species of bird in the Dicruridae family.It is found in the Indian Subcontinent and Southeast Asia, ranging across Bangladesh, Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Thailand, and Vietnam...
, 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 Lankan form lophorinus used to be treated as a subspecies due to the suggestion that it formed hybrids with ceylonicus is considered a separate species in newer taxonomic treatments on the basis of their overlapping ranges. Specimens of the nominate form have sometimes been confused with lophorinus. 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
Banggai
Banggai Archipelago is a group of islands, which is located at the far eastern end of Central Sulawesi, Indonesia. It makes up a newly established regency after splitting out of Luwuk. It is surrounded by the Banda Sea's Gulf of Tolo , and the Molucca Sea...
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.
Distribution and habitat
The distribution range of this species extends from the western Himalayas to the eastern Himalayas and Mishmi Hills in the foothills below 4000 feet. Continuing into the west to the islands of Borneo and Java in the east through the mainland and islands. They are found mainly in forest habitats.Behaviour and ecology
Like other drongos, these feed mainly on insects but also feed on fruits and visit flowering trees for nectar. Having short legs, they sit upright and are often perched on high and exposed branches. They are aggressive and will sometimes mob larger birds especially when nesting. They are often active at dusk.Their calls are extremely varied and include monotonously repeated whistles, metallic and nasal sounds as well as more complex notes and imitations of other birds. They begin calling from as early as 4 am in moonlight often with a metallic tunk-tunk-tunk series. They have an ability to accurately mimic alarm call
Alarm call
In the field of animal communication, an alarm signal is an antipredator adaptation referring to various signals emitted by social animals in response to danger. Many primates and birds have elaborate alarm calls for warning conspecifics of approaching predators. For example, the characteristic...
s of other birds that are learnt through interactions in mixed-species flocks. This is quite unusual, as avian vocal mimicry has hitherto been believed to be ignorant of the original context of the imitated vocalization. African Grey Parrot
African Grey Parrot
The African Grey Parrot , also known as the Grey Parrot, is a medium-sized parrot found in the primary and secondary rainforest of West and Central Africa. Experts regard it as one of the most intelligent birds. They feed primarily on palm nuts, seeds, fruits, leafy matter, but have been observed...
s are known to use imitated human speech in correct context, but do not show this behavior in nature. This drongo's context-sensitive use of other species' alarm calls is thus analogous to a human learning useful short phrases and exclamations in a number of foreign languages. A special alarm note is raised in the presence of Shikra
Shikra
The Shikra is a small bird of prey in the family Accipitridae found widely distributed in Asia and Africa where it is also called the Little Banded Goshawk. The African forms may represent a separate species but have usually been considered as subspecies of the Shikra...
s that has been transcribed as a loud kwei-kwei-kwei...shee-cuckoo-sheecuckoo-sheecuckoo-why!. They have been said to imitate raptor calls so as to alarm other birds and steal prey from them in the ensuing panic. They are also known to imitate the calls of species (known sometimes even to fluff up and moving head and body like a Jungle Babbler) that typically are members of mixed-species flocks such as babblers and it has been suggested that this has a role in the formation of mixed-species flocks. In some places they have been found to be kleptoparasitic
Kleptoparasitism
Kleptoparasitism or cleptoparasitism is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food...
on others in mixed-species flock, particularly Laughingthrushes but they are most often involved in mutualistic and commensal relations. Several observers have found this drongo associating with foraging woodpeckers and there is a report of one following a troop of macaques.
The Greater Racket-tailed Drongo is a resident breeder throughout its range. The breeding season in India is April to August. Their courtship display may involve hops and turns on branches with play behaviour involving dropping an object and picking it in mid air. Their cup nest is built in the fork of a tree and the usual clutch is three to four egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s. The eggs are creamy white with blotches of reddish brown which are more dense on the broad end.
In culture
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 DrongoBlack Drongo
The Black Drongo , also known as the King Crow, is a small Asian passerine bird of the drongo family Dicruridae. Previously considered a subspecies of the African Fork-tailed Drongo , it is now recognized as a full species...
and in other places as the Bhimraj or Bhringaraj. 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. The great racket tailed drongo is considered as a good omen as opposed to the related species black drongo which is considered as a bad omen.