Nicobar Bulbul
Encyclopedia
Found only on the Nicobar Islands
of India
, the Nicobar Bulbul is a songbird
species
in the bulbul
family
(Pycnonotidae). Its scientific name is Hypsipetes virescens as long as Ixos
is recognized as a distinct genus
.
Some sources merge Ixos into Hypsipetes
, probably based on the major taxonomic error committed in the Sibley taxonomy, where I. virescens – the type species
of Ixos – was placed in Hypsipetes. In these works, H. virescens refers to the Sunda Bulbul
(properly I. virescens), whose senior homonym was already established by Coenraad Jacob Temminck
in 1825, whereas Edward Blyth
gave the specific name virescens to the Nicobar Bulbul only in 1845. Thus, the Nicobar Bulbul is often known under the junior synonym Hypsipetes nicobariensis, although this name is not legitimate: it would properly be Ixos nicobariensis if the genera are merged, because Hypsipetes was established after Ixos.
is a rather drab, nondescript species without a crest. Its wings, back and tail are dull dusky green; the face is lighter, and the throat and underside are yellowish-white. The most prominent feature is a sooty-brown cap reaching down to eye height.
It produces chattering calls, similar to those of the Black Bulbul
(H. leucocephalus).
of India
, where it only occurs in the central group, namely Bompoka, Camorta
, Katchall, Nancowry
, Teressa
, Tillanchong and Trinkat; a supposed 19th century record from Pilo Milo in the southern group is nowadays generally dismissed.
Its natural habitat
s are subtropical and tropical moist lowland primary and secondary forest
. It also visits plantation
s, rural gardens, and occasionally urban area
s and grassland
. Restricted to a few islands, it is threatened with extinction in the long-term future. In the early 1990s
already, though the species was still found on every major island in its range, only single birds or families were usually seen except on Katchall and Teressa. Only in some places on the former it was still as common then as it used to be 100 years ago. At present, it manages to hold its own, but only barely, and habitat loss may have been severe enough to accelerate its decline to dangerous proportions. With altogether a few thousand adult birds remaining, it is classifed as Near Threatened
by the IUCN.
such as logging
for rubber plantations has encroached upon the native forest, and while more sustainable forest uses by humans are tolerated well enough, monoculture
s are of little use to this island endemic and are utilized only infrequently. An increasing human population has resulted in much clear-cutting in the mid-late 20th century, and expansion of military installations in these frontier islands has also resulted in considerable habitat destruction.
Also, the Andaman
Red-whiskered Bulbul
(Pycnonotus jocosus whistleri) was introduced to Camorta
by the British
; it was later brought to other islands in the Nancowry
group by locals, who, like many people elsewhere, consider the Red-whiskered Bulbul a popular pet
. The two bulbuls presumably compete for food, nesting locations and other resources, and if the human-assisted P. j. whistleri is not actually displacing H. virescens, being well-established on Katchall, Nancowry, Teressa
and Trinkat it is certainly keeping the Nicobar Bulbul's population lower than it could be. On the other hand, there is no reason to suppose that the native species is an inferior competitor; rather the two bulbuls' populations soon seem to reach an equilibrium: on Katchall the Red-whiskered Bulbul was established in the 1910s or so already, and this has not prevented healthy Nicobar Bulbul stocks from persisting on that island to our time.
The Nicobar Islands were hit hard by the 2004 Indian Ocean tsunami, and the central group was perhaps most severely affected, with at least hundreds, maybe thousands of its inhabitants dead. On Katchall there was perhaps the highest loss of life in the entire Nicobars, but this was to catastrophic destruction of settled areas and much of the island's interior forest was not affected. Trinkat was literally torn into three pieces, while on Camorta flooding was extreme in the northern part only. Nancowry on the other hand suffered rather little damage overall. On Teressa, the low-lying plains suffered extensive flooding, bisecting the island in fact, but the remaining forest fragments are mostly confined to the hills and were spared. Bompoka and Tillanchong, though small, are quite steep and consequently were not much affected. Though the effect of the Nicobar Bulbul's population on Trinkat for example might have been devastating, the tsunami is not known to have significantly harmed the overall stocks of the species.
Nicobar Islands
The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean...
of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, the Nicobar Bulbul is a songbird
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the bulbul
Bulbul
Bulbuls are a family, Pycnonotidae, of medium-sized passerine songbirds. Many forest species are known as greenbuls. The family is distributed across most of Africa and into the Middle East, tropical Asia to Indonesia, and north as far as Japan. A few insular species occur on the tropical islands...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
(Pycnonotidae). Its scientific name is Hypsipetes virescens as long as Ixos
Ixos
Ixos is a songbird genus in the bulbul family, Pycnonotidae. It provisionally contains the following species:* Yellowish Bulbul, Ixos everetti* Streaked Bulbul, Ixos malaccensis...
is recognized as a distinct genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
Some sources merge Ixos into Hypsipetes
Hypsipetes
Hypsipetes is a genus of bulbuls, songbirds in the family Pycnonotidae. Most of its species birds occur in tropical forests around the Indian Ocean. But while the genus is quite diverse in the Madagascar region at the western end of its range it does not reach the African mainland.Most Hypsipetes...
, probably based on the major taxonomic error committed in the Sibley taxonomy, where I. virescens – the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Ixos – was placed in Hypsipetes. In these works, H. virescens refers to the Sunda Bulbul
Sunda Bulbul
The Sunda Bulbul or Green-winged Bulbul is a songbird species in the bulbul family . It is the type species of the genus Ixos....
(properly I. virescens), whose senior homonym was already established by Coenraad Jacob Temminck
Coenraad Jacob Temminck
Coenraad Jacob Temminck was a Dutch aristocrat and zoologist.Temminck was the first director of the National Natural History Museum at Leiden from 1820 until his death. His Manuel d'ornithologie, ou Tableau systematique des oiseaux qui se trouvent en Europe was the standard work on European birds...
in 1825, whereas Edward Blyth
Edward Blyth
Edward Blyth was an English zoologist and pharmacist. He was one of the founders of zoology in India....
gave the specific name virescens to the Nicobar Bulbul only in 1845. Thus, the Nicobar Bulbul is often known under the junior synonym Hypsipetes nicobariensis, although this name is not legitimate: it would properly be Ixos nicobariensis if the genera are merged, because Hypsipetes was established after Ixos.
Description
This 20 cm-long bulbulBulbul
Bulbuls are a family, Pycnonotidae, of medium-sized passerine songbirds. Many forest species are known as greenbuls. The family is distributed across most of Africa and into the Middle East, tropical Asia to Indonesia, and north as far as Japan. A few insular species occur on the tropical islands...
is a rather drab, nondescript species without a crest. Its wings, back and tail are dull dusky green; the face is lighter, and the throat and underside are yellowish-white. The most prominent feature is a sooty-brown cap reaching down to eye height.
It produces chattering calls, similar to those of the Black Bulbul
Black Bulbul
The Black Bulbul , also known as the Himalayan Black Bulbul, Asian Black Bulbul or Square-tailed Bulbul, is a member of the bulbul family of passerine birds. It is found in southern Asia from India east to southern China. It is the type species of the genus Hypsipetes, established by Nicholas...
(H. leucocephalus).
Distribution, ecology and status
It is endemic to the Nicobar IslandsNicobar Islands
The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean...
of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, where it only occurs in the central group, namely Bompoka, Camorta
Camorta
Camorta is one of the Nicobar Islands, India. Its area is 188 km²....
, Katchall, Nancowry
Nancowry
Nancowry refers both to a single island and to the group of adjoining islands that make up the central part of the Nicobar Islands chain, located in the northeast Indian Ocean between the Bay of Bengal and the Andaman Sea....
, Teressa
Teressa (Nicobar Islands)
Teressa is one of the Nicobar Islands, India. Austria and Denmark claimed Nicobar Islands as colony. Teressa is named after the Austrian Arch-duchess Maria Theresia....
, Tillanchong and Trinkat; a supposed 19th century record from Pilo Milo in the southern group is nowadays generally dismissed.
Its natural habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s are subtropical and tropical moist lowland primary and secondary forest
Secondary forest
A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...
. It also visits plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
s, rural gardens, and occasionally urban area
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
s and grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
. Restricted to a few islands, it is threatened with extinction in the long-term future. In the early 1990s
1990s
File:1990s decade montage.png|From left, clockwise: The Hubble Space Telescope floats in space after it was taken up in 1990; American F-16s and F-15s fly over burning oil fields and the USA Lexie in Operation Desert Storm, also known as the 1991 Gulf War; The signing of the Oslo Accords on...
already, though the species was still found on every major island in its range, only single birds or families were usually seen except on Katchall and Teressa. Only in some places on the former it was still as common then as it used to be 100 years ago. At present, it manages to hold its own, but only barely, and habitat loss may have been severe enough to accelerate its decline to dangerous proportions. With altogether a few thousand adult birds remaining, it is classifed as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
by the IUCN.
Factors affecting decline
Several factors have contributed to this species' decline. For one thing, habitat destructionHabitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
such as logging
Logging
Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...
for rubber plantations has encroached upon the native forest, and while more sustainable forest uses by humans are tolerated well enough, monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
s are of little use to this island endemic and are utilized only infrequently. An increasing human population has resulted in much clear-cutting in the mid-late 20th century, and expansion of military installations in these frontier islands has also resulted in considerable habitat destruction.
Also, the Andaman
Andaman Islands
The Andaman Islands are a group of Indian Ocean archipelagic islands in the Bay of Bengal between India to the west, and Burma , to the north and east...
Red-whiskered Bulbul
Red-whiskered Bulbul
The Red-whiskered Bulbul is a passerine bird found in Asia. It is a member of the bulbul family. It is a resident frugivore found mainly in tropical Asia. It has been introduced in many tropical areas of the world where populations have established themselves...
(Pycnonotus jocosus whistleri) was introduced to Camorta
Camorta
Camorta is one of the Nicobar Islands, India. Its area is 188 km²....
by the British
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
; it was later brought to other islands in the Nancowry
Nancowry
Nancowry refers both to a single island and to the group of adjoining islands that make up the central part of the Nicobar Islands chain, located in the northeast Indian Ocean between the Bay of Bengal and the Andaman Sea....
group by locals, who, like many people elsewhere, consider the Red-whiskered Bulbul a popular pet
Pet
A pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
. The two bulbuls presumably compete for food, nesting locations and other resources, and if the human-assisted P. j. whistleri is not actually displacing H. virescens, being well-established on Katchall, Nancowry, Teressa
Teressa (Nicobar Islands)
Teressa is one of the Nicobar Islands, India. Austria and Denmark claimed Nicobar Islands as colony. Teressa is named after the Austrian Arch-duchess Maria Theresia....
and Trinkat it is certainly keeping the Nicobar Bulbul's population lower than it could be. On the other hand, there is no reason to suppose that the native species is an inferior competitor; rather the two bulbuls' populations soon seem to reach an equilibrium: on Katchall the Red-whiskered Bulbul was established in the 1910s or so already, and this has not prevented healthy Nicobar Bulbul stocks from persisting on that island to our time.
The Nicobar Islands were hit hard by the 2004 Indian Ocean tsunami, and the central group was perhaps most severely affected, with at least hundreds, maybe thousands of its inhabitants dead. On Katchall there was perhaps the highest loss of life in the entire Nicobars, but this was to catastrophic destruction of settled areas and much of the island's interior forest was not affected. Trinkat was literally torn into three pieces, while on Camorta flooding was extreme in the northern part only. Nancowry on the other hand suffered rather little damage overall. On Teressa, the low-lying plains suffered extensive flooding, bisecting the island in fact, but the remaining forest fragments are mostly confined to the hills and were spared. Bompoka and Tillanchong, though small, are quite steep and consequently were not much affected. Though the effect of the Nicobar Bulbul's population on Trinkat for example might have been devastating, the tsunami is not known to have significantly harmed the overall stocks of the species.