The Red-vented Bulbul (Pycnonotus cafer) is a member of the bulbul family of passerines. It is resident breeder across the Indian Subcontinent, including Sri Lanka extending east to Burma and parts of Tibet. It has been introduced in many other parts of the world and has established itself in the wild on several Pacific islands including Fiji, Samoa, Tonga, and Hawaii. It has also established itself in parts of Dubai, the United Arab Emirates and New Zealand. It is included in the list of the world's 100 worst invasive alien species.^[2]

Taxonomy

P. c. cafer (Ernakulam, India)

The Red-vented Bulbul was originally described by Linnaeus in 1766. Several populations of this widespread species have been named as subspecies (or races). The nominate race is found in southern India.^[3] The type locality of Pondicherry was designated by Erwin Stresemann.^[4] The race in the western part is intermedius and is found in Kashmir and Kohat down to the Salt Range and along the Himalayas to Kumaon. The race bengalensis is found in the Himalayas from Nepal east to Assam. South of these two forms are pallidus to the west south to Ahmednagar and saturatus along the east, south to the Godavari. There are no distinct boundaries to these racial forms and recent works do not recognize pallidus and saturatus (designated by Whistler & Kinnear, 1932 for the northeastern Peninsular India) but accept the desert form humayuni from Sindh and northwestern India, northeast Indian stanfordii (=stanfordi Deignan, 1949) and the Sri Lankan race haemorrhous (=haemorrhousus (J. F. Gmelin, 1789) ).^[5] Race melanchimus is found in Southern Burma and northern Thailand.^[6]

Race chrysorrhoides is found in China. Two formerly designated races nigropileus in Southern Burma and burmanicus of Northern Burma are considered as hybrids.^[6][7][8]

Description

Underside of race bengalensis

The Red-vented Bulbul is easily identified by its short crest giving the head a squarish appearance. The body is dark brown with a scaly pattern while the head is darker or black. The rump is white while the vent is red. The black tail is tipped in white. The Himalayan races have a more prominent crest and are more streaked on the underside. The Race intermedius of the Western Himalayas has a black hood extending to the mid-breast. Population bengalensis of Central and Eastern Himalayas and the Gangetic plain has a dark hood, lacks the scale like pattern on the underside and instead has dark streaks on the paler lower belly. Race stanfordi of the South Assam hills is similar to intermedius. The desert race humayuni has a paler brown mantle. The nominate race cafer is found in Peninsular India. Northeast Indian race wetmorei is between cafer, humayuni and bengalensis. about 20 cm in length, with a long tail. Sri Lankan race haemorrhous (=haemorrhousus^[6]) has a dark mantle with narrow pale edges. Race humayuni is known to hybridize with Pycnonotus leucogenys and these hybrids were once described as a subspecies magrathi marked by their pale rumps and yellow-orange or pink vents.^[9] In eastern Myanmar there is some natural hybridization with Pycnonotus aurigaster.^[5][10]

P. leucogenys x P. c. humayuni hybrid (magrathi)

Sexes are similar in plumage, but young birds are duller than adults.^[5] The typical call has been transcribed as ginger beer but a number of sharp single note calls likened as pick are also produced. Their alarm calls are usually responded to and heeded by many other species of bird.^[11]

Melanistic as well as leucistic individuals have been noted.^{[12][13][14][15]}

Habitat and distribution

This is a bird of dry scrub, open forest, plains and cultivated lands.^[5] In its native range it is rarely found in mature forests. A study based on 54 localities in India concluded that vegetation is the single most important factor that determines the distribution of the species.^[16]

It has been introduced into Hawaii, Fiji and New Zealand. They were introduced to Samoa in 1943 and became common on Upolu by 1957. Red-vented Bulbuls were introduced to Fiji around 1903 by indentured labourers from India.^[17] They established on the Tongan islands of Tongatapu and Niuafo'ou. They were introduced into Melbourne around 1917 but were not seen after 1942.^[18] They established in Auckland in the 1950s but were exterminated.^[19] They prefer the dry lowland regions in these introduced regions.^[20][21] They are considered as pests because of their habit of damaging fruit crops. Methiocarb and ziram have been used to protect cultivated Dendrobium orchids in Hawaii from damage by these birds. These birds learn to avoid the repellent chemicals.^[22] They can also disperse the seeds of invasive plants like Lantana camara^[23] and Miconia calvescens.^[24][25]

Behaviour and ecology

Nest

Red-vented bulbuls feed mainly on fruits, petals of flowers,^[26] nectar, insects and occasionally geckos.^{[27][28][29][30][31][32]} They have also been seen feeding on the leaves of Medicago sativa.^[23]

Red-vented bulbuls build their nests in bushes at a height of around 2–3 m (7–10 ft; two or three eggs is a typical clutch. Nests are occasionally built inside houses^[33][34] or in a hole in a mud bank.^[35] In one instance, a nest was found on a floating mat of Water hyacinth leaves^[36] and another observer noted a pair nesting inside a regularly used bus.^[37] Nests in tree cavities have also been noted.^[38]

They breed from June to September. The eggs are pale-pinkish with spots of darker red more dense at the broad end.^[39] They are capable of having multiple clutches in a year. Nests are small flat cups made of small twigs but sometimes making use of metal wires.^[40] The eggs hatch after about 14 days.^[11] Both parents feed the chicks and on feeding trips wait for the young to excrete, swallowing the faecal sacs produced.^[41] The Pied Crested Cuckoo is a brood parasite of this species.^[42] Fires, heavy rains and predators are the main causes of fledgeling mortality in scrub habitats in southern India.^[43]

Eggs inside the nest

Their vocalizations are usually stereotyped and they call throughout the year. However a number of distinct call types have been identified including roosting, begging, greeting, flight and two kinds of alarm calls.^[44]

	Call Call of Redvented Bulbul
Problems listening to this file? See media help.

They are important dispersers of seed of plants such as Carissa spinarum.^[45]

The Red-vented Bulbul was among the first animals other than humans that was found to be incapable of synthesizing vitamin C.^[46][47] However a large number of birds were later found to likewise lack the ability to synthesize vitamin C.^[48]

Like most birds, these bulbuls are hosts to coccidian blood parasites (Isospora sp.^[49]) while some bird lice such as Menacanthus guldum (Ansari 1951 Proc. Natl. Inst. Sci. India 17:40) have been described as ectoparasites.^[50]

Along with Red-whiskered Bulbuls this species has led to changes in the population dynamics of butterfly morphs on the island of Oahu in Hawaii. Here the population of white morphs of the Danaus plexippus butterfly have risen over a period of 20 years due to predation of the orange morphs by these bulbuls.^[51]

In culture

P. c. haemorrhous (Colombo, Sri Lanka)

In 19th Century India these birds were frequently kept as cage pets and for fighting especially in the Carnatic region. They would be held on the finger with a thread attached and when they fought they would seize the red feathers of the opponents.^[39]

Indians frequently tame it and carry it about the bazaars, tied with a string to the finger or to a little crutched perch, which is often made of precious metals or jade; while there are few Europeans who do not recollect Eha's immortal phrase anent the red patch in the seat of its trousers.

—Hugh Whistler^[3]

Being well known in culture they have been referred to by many local names including Kala bulbul (=black bulbul), Bulbuli, and Guldum in Hindi, Kala painju in Himachal Pradesh; Assamese: Bulbuli sorai; Cachar: Dao bulip; Dafla: Nili betom; Lepcha: Mancleph-pho; Naga: Inrui bulip; Bhutan: Paklom; Bhil: Peetrolyo; Gujarati: Hadiyo bulbul; Kutchi: Bhilbhil; Marathi: Lalbudya bulbul; Oriya: Bulubul; Tamil: Kondanchiradi, Konda-lati, Kondai kuruvi; Telugu: Pigli-pitta; Malayalam: Nattu bulbul; Kannada: Kempu dwarada pikalara; Sinhala: Konde kurulla.^[52]

References