Alström's warbler (''Phylloscopus soror''), or the plain-tailed warbler, is a species of

Old World warbler The Old World warblers are a large group of birds formerly grouped together in the bird family Sylviidae. They are not closely related to the New World warblers. The family held over 400 species in over 70 genera, and were the source of much taxo ...

in the family Phylloscopidae. It was first described in 1999. It breeds only in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

and winters as far as

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...

Cambodia Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...

and

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

. Its natural

habitat In ecology, habitat refers to the array of resources, 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 manifestation of its ...

is temperate

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

Habitat and migration

Alström's warbler often

forages Foraging is searching for wild food resources. It affects an animal's Fitness (biology), fitness because it plays an important role in an animal's ability to survive and reproduce. Optimal foraging theory, Foraging theory is a branch of behaviora ...

in a low, dense growth of forests. This bird is known to eat insects and catch prey during short flights. The bird is not currently globally threatened. This bird has a very large range and does not approach the potential of being a

vulnerable species A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...

. The warbler typically breeds in warmer,

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

areas. These areas are found within evergreen broadleaf forest zones and lush

undergrowth In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above ...

in mature forests. It has a scattered breeding range across central and eastern China. The warbler tends to breed in bushes and small trees of low to moderate height, in recently cleared areas. This bird is a migratory species. It migrates during the winter to southern Myanmar, Thailand, Cambodia, southern Vietnam, and southern China.

Genus

Alström's warbler was previously placed in the genus ''Seicercus''. A

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study published in 2018 found that neither '' Phylloscopus'' nor ''Seicercus'' were

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. In the subsequent reorganization the two genera were merged into ''Phylloscopus'' which has priority under the rules of the

International Commission on Zoological Nomenclature The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries. Orga ...

. The

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

honours the Swedish ornithologist

Per Alström ''Per'' Johan Alström (born 9 April 1961) is a Swedish Professor of ornithology. He does research in Taxonomy (biology), taxonomy, systematics, and evolution, with birds in Asia as a specialty. Alström works at the Department of Ecology and Genet ...

Appearance and identification

Alström's warbler measures 11-12 cm in size. The female is on average smaller than the male. The Alström's warbler can be commonly mistaken for Martens's, Gray-crowned, White-speckled, and Bianchi's

warblers Various Passeriformes (perching birds) are commonly referred to as warblers. They are not necessarily closely related to one another, but share some characteristics, such as being fairly small, vocal, and insectivorous. Sylvioid warblers T ...

. The bird has a greyish-black color that fades on the forehead as well as a mix of green that surrounds the eyes. The underside of the bird is a vibrant yellowish-green color whereas the wings and back have a grey crown with black stripes. This bird has a distinct yellow

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 ...

that may diffuse above the eye. To distinguish this bird from others, the Alström's warbler is larger billed, smaller tailed, and has a more distinct white lining in the outer tail feathers than Martens's and Gray-crowned warblers.

Breeding

Based on male singing activity, the mating activity of the warbler is from May to June. The non-breeding distribution and migratory periods are not fully known at this time. This bird has been located in southern China outside of its breeding range from early September to early October. The warbler has been seen in Thailand during mid-September, as well as in southern Vietnam in late September. The non-breeding warbler has been observed in southern Myanmar up until mid-April. The warbler has been spotted on Chinese breeding grounds in late April. Its distribution in the non-breeding season is hard to estimate because there is an overlap of non-singing similar species which makes identification very difficult.

Birdsong

This bird has a very simple song, which consists of short, quick

strophes A strophe () is a poetic term originally referring to the first part of the ode in Ancient Greek tragedy, followed by the antistrophe and epode. The term has been extended to also mean a structural division of a poem containing stanzas of varyin ...

, typically with a short ''chip'' as an introductory note. The introductory note is followed by 2-5 short, whistled notes. The whistled notes are arranged into an element group that is usually given 2-4 times, followed by a pause. The warbler has a distinctly higher-pitched and broader

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

span than the ''P. valentini''. The song can be easily simplified by a brief ''che-witchy-chew-witchy-chew''.

References

Alström's warbler Alström's warbler (''Phylloscopus soror''), or the plain-tailed warbler, is a species of Old World warbler in the family Phylloscopidae. It was first described in 1999. It breeds only in China and winters as far as Thailand Thailand, ...

Birds of China

Taxonomy articles created by Polbot {{Phylloscopidae-stub