The Taiwan bush warbler (''Locustella alishanensis'') is a species of

Old World warbler Old World warblers are a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the ci ...

in the family

Locustellidae Locustellidae is a newly recognized family of small insectivorous songbirds ("warblers"), formerly placed in the Old World warbler "wastebin" family. It contains the grass warblers, grassbirds, and the ''Bradypterus'' "bush warblers". These bird ...

. It is found only in

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

. Its natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

is undergrowth and

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

in elevation. It was first recorded in 1917 and named as a distinct species in 2000. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

(IUCN) has assessed it as a

least-concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

species.

Taxonomy

This bush warbler was first recorded from Alishan in 1917. At first, it was thought to be a population of ''Bradypterus luteoventris''. In 1952,

Jean Théodore Delacour Jean Théodore Delacour (26 September 1890 – 5 November 1985) was a French ornithologist and aviculturist. He later became American. He was renowned for not only discovering but also rearing some of the rarest birds in the world. He establish ...

placed it within subspecies ''idoneus'' of ''B. seebohmi'' (now split into several species). Later authorities placed it in subspecies ''melanorhynchus''. In the late 1980s, its

song A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetitio ...

was found to be very distinctive, unlike other related species. In 2000,

Pamela C. Rasmussen Pamela Cecile Rasmussen (born October 16, 1959) is an American ornithologist and expert on Asian birds. She was formerly a research associate at the Smithsonian Institution in Washington, D.C., and is based at the Michigan State University. She ...

, Philip D. Round,

Edward C. Dickinson Edward Clive Dickinson (born 6 March 1938) is a British ornithologist specialising in the taxonomy of southeast Asian birds. Biography Edward Dickinson was born in 1938, in Paget Parish, Bermuda, the son of Lionel Gilbert Dickinson and Eileen Dick ...

and

Frank Rozendaal Frank Gerard Rozendaal (9 May 1957 – 3 December 2013) was a Dutch ornithologist who in particular did research on the Southeast Asian avifauna. He also contributed to the taxonomy of bats. After field trips in Europe and the Near East he conduc ...

described the population as a distinct species, ''Bradypterus alishanensis'', based on its distinctive song and morphological observations. It was later transferred to the genus '' Locustella''. A 2015 study concluded that it was the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of the

russet bush warbler The russet bush warbler (''Locustella mandelli'') is a songbird species. Formerly placed in the "Old World warbler" assemblage, it is now placed in the newly recognized family Locustellidae. ''B. mandelli'' was until recently considered a subsp ...

(''Locustella mandelli'')

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

, being genetically more divergent than the species in the complex.

Description

The Taiwan bush warbler is about long and weighs about . The male and female are alike. The head is dull rufous-brown, the crown having narrow dark tips. The indistinct

supercilium The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also ...

and

eye-ring The eye-ring of a bird is a ring of tiny feathers that surrounds the orbital ring, a ring of bare skin immediately surrounding a bird's eye. The eye-ring is often decorative, and its colour may contrast with adjoining plumage. The ring of feather ...

are pale buff. The upperparts, from the mantle to the wings and tail, are dull russet-brown. The chin and throat are white, the lower throat usually having spots. The upper breast is greyish brown, and the lower breast and belly are white. The undertail coverts are dark rufous-brown with warm-coloured tips. The

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for food ...

is black, and in winter the lower mandible is sometimes pale. The feet are pale pink, and the eyes are reddish brown. The juvenile bird has a brownish breast and does not have spots.

Distribution and habitat

This species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Taiwan. It breeds in mountains above sea level, sometimes below . It does not migrate, but in winter, it may move to lower elevations. Its habitat is deciduous and coniferous woodland with thick undergrowth consisting of grasses, shrubs or ferns, and also grass and bamboo near the

tree line The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowp ...

. It is present in habitats disturbed by humans.

Behaviour

The Taiwan bush warbler's behaviour is very similar to that of the russet bush warbler. The Taiwan bush warbler mostly sings in the morning and evening, starting in late March, and it has also been heard in winter. Its song is a repeated sequence of one monotone whistle and three or four clicks; the sequence is usually repeated more than ten times, ending with the whistle. This is unlike the nasal and metallic song of the russet bush warbler and the staccato song of the

brown bush warbler The brown bush warbler (''Locustella luteoventris'') is a songbird species. Formerly placed in the "Old World warbler" assemblage as ''Bradypterus luteoventrus'', it is now placed in the newly recognized family Locustellidae. It is found in Ban ...

. Calls include a scratchy ''ksh ksh ksh'', a sharp ''tick'' and a ''stip''. It breeds in May and June, and possibly as late as August. The nest is built in grass, and there are two eggs per clutch. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen has insects in its stomach.

Status

Considered to be common, this species is not regarded as threatened, and the IUCN has assessed it as a

least-concern species A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

{{Taxonbar, from=Q27075489

Taiwan bush warbler The Taiwan bush warbler (''Locustella alishanensis'') is a species of Old World warbler in the family Locustellidae. It is found only in Taiwan. Its natural habitat is undergrowth and grassland in elevation. It was first recorded in 1917 and nam ...

Endemic birds of Taiwan

Taxonomy articles created by Polbot