Large-billed Reed-warbler
Encyclopedia
The Large-billed Reed-warbler (Acrocephalus orinus) is an Old World warbler
in the genus Acrocephalus
. The species has been dubbed as "the world's least known bird". It was known from a single specimen collected in India in 1867 and rediscovered in the wild in Thailand
in 2006. The identity of the bird caught in Thailand was established by matching DNA
sequences extracted from feather
s; the bird was released. After the rediscovery in the wild a second specimen was discovered amid Acrocephalus dumetorum specimens in the collections of the Natural History Museum at Tring
. A breeding area was found in Afghanistan in 2009 and studies in 2011 pointed to its breeding in Kazhakstan and Tajikistan.
This species has the upper plumage and visible portions of wings and tail olive-brown while the underside is pale creamy with the underwing and axillaries paler.
The length is about 5 inches (127 mm) with the tail being 2.3 inches (58.4 mm) and the wing 2.4 inches (61 mm) long. The tarsus is 0.85 inches (21.6 mm) while the bill from gape
is 0.8 inches (20.3 mm). The first primary measures 0.35 inches (8.9 mm) while the second is intermediate in length between the ninth and tenth. The closed tail appears graduated with the difference between the longest and shortest feathers being 0.4 inches (10.2 mm). The type specimen was obtained in the Sutlej valley ("Sukedje valley") not far from Rampur.
The upper mandible is dark, but the cutting edges and entire lower mandible are pale. The tarsi, toes and claws appear pale brown. The hind claw is longer than in dumetorum. The tips of the tail feathers are pointed and more acutely lanceolate than in dumetorum or Acrocephalus concinens. The primary tips are broad and rather squarer. Recent observers note that it has a habit of fanning out its tail open as it forages.
The specimens from Afghanistan and Kazakhstan suggest that they breed in Central Asia and moult indicates that they migrate along the Himalayas to winter in northern India and Southeast Asia. Sequence variation points to a stable or shrinking population structure.
in the Sutlej Valley near Rampoor, Himachal Pradesh
, India
on 13 November 1867. This specimen (BMNH registration no. 1886.7.8. 1742) was first provisionally described as Phyllopneuste macrorhyncha (Hume
, 1869) but the name was changed two years later to Acrocephalus macrorhynchus (Hume, 1871). H C Oberholser
however pointed out in 1905 that this was unacceptable because a specimen from Egypt described by von Müller in 1853 as Calamoherpe macrorhyncha turned out to be Acrocephalus stentoreus; Acrocephalus macrorhynchus was abandoned in favour of A. orinus. The identity of the species was in question and until 2002 was considered as a synonym of the Clamorous Reed Warbler (Acrocephalus stentoreus). Some others considered it an aberrant Blyth's Reed Warbler. A recent re-check of the morphology and the mtDNA suggested that it was a distinct species. An additional ten new specimens in collections were identified in 2008. These included specimens collected by John Biddulph
from Gilgit and W N Koelz
from Zebak.
, Thailand
by ornithologist Philip Round of Mahidol University
. The bird was ringed
and two feathers were extracted; DNA from them was found to match the DNA of the 1867 specimen.
Based on the short and rounded wings, earlier studies had suggested that the species was likely to be a short-distant migrant or a resident. The rediscoveries of a second museum specimen from a different location and the wild specimen from Thailand suggest that this may not be so.
Some field identifications from West Bengal and central India were subsequently reported based on behaviour but captured specimens did not appear to match the species.
A breeding site of the Large-billed Reed-warbler Acrocephalus orinus, was discovered in the Wakhan Corridor
of the Pamir
of north-eastern Afghanistan
by Researcher Robert Timmins of the Wildlife Conservation Society who was studying aviary communities in the Pamir Mountains. He came across a small brown warbler and recorded its song. Dr. Timmins did not realize the importance of his discovery until he visited a Natural History Museum in Tring, England. There he examined a specimen of a large-billed reed warbler. It was the bird he had seen and recorded.
Ornithologists verified
his discovery by capturing and releasing almost 20 specimens of the bird in 2009, the largest number ever recorded, using a combination of field observations, museum specimens, DNA sequencing, and also the first known audio recording of the species that were already made in 2008.
A study by Russian ornithologists in 2011 indicated that the species had been misidentified as A. dumetorum in museum collections and that the species may be breeding in Tajikistan, Kyrgyzstan, eastern Uzbekistan and south-eastern Kazakhstan.
Old World warbler
The "Old World Warblers" is the name used to describe 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 cisticolas into...
in the genus Acrocephalus
Acrocephalus
The Acrocephalus warblers are small, insectivorous passerine birds belonging to the genus Acrocephalus. Formerly in the paraphyletic Old World warbler assemblage, they are now separated as the namesake of the marsh- and tree-warbler family Acrocephalidae...
. The species has been dubbed as "the world's least known bird". It was known from a single specimen collected in India in 1867 and rediscovered in the wild in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
in 2006. The identity of the bird caught in Thailand was established by matching DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
sequences extracted from feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
s; the bird was released. After the rediscovery in the wild a second specimen was discovered amid Acrocephalus dumetorum specimens in the collections of the Natural History Museum at Tring
Tring
Tring is a small market town and also a civil parish in the Chiltern Hills in Hertfordshire, England. Situated north-west of London and linked to London by the old Roman road of Akeman Street, by the modern A41, by the Grand Union Canal and by rail lines to Euston Station, Tring is now largely a...
. A breeding area was found in Afghanistan in 2009 and studies in 2011 pointed to its breeding in Kazhakstan and Tajikistan.
Description
The length is about 5 inches (127 mm) with the tail being 2.3 inches (58.4 mm) and the wing 2.4 inches (61 mm) long. The tarsus is 0.85 inches (21.6 mm) while the bill from gape
Gape
In bird anatomy, the gape is the interior of the open mouth of a bird and the gape flange is the region where the two mandibles join together, at the base of the beak...
is 0.8 inches (20.3 mm). The first primary measures 0.35 inches (8.9 mm) while the second is intermediate in length between the ninth and tenth. The closed tail appears graduated with the difference between the longest and shortest feathers being 0.4 inches (10.2 mm). The type specimen was obtained in the Sutlej valley ("Sukedje valley") not far from Rampur.
The upper mandible is dark, but the cutting edges and entire lower mandible are pale. The tarsi, toes and claws appear pale brown. The hind claw is longer than in dumetorum. The tips of the tail feathers are pointed and more acutely lanceolate than in dumetorum or Acrocephalus concinens. The primary tips are broad and rather squarer. Recent observers note that it has a habit of fanning out its tail open as it forages.
The specimens from Afghanistan and Kazakhstan suggest that they breed in Central Asia and moult indicates that they migrate along the Himalayas to winter in northern India and Southeast Asia. Sequence variation points to a stable or shrinking population structure.
History
It was first collected by Allan Octavian HumeAllan Octavian Hume
Allan Octavian Hume was a civil servant, political reformer and amateur ornithologist in British India. He was one of the founders of the Indian National Congress, a political party that was later to lead the Indian independence movement...
in the Sutlej Valley near Rampoor, Himachal Pradesh
Himachal Pradesh
Himachal Pradesh is a state in Northern India. It is spread over , and is bordered by the Indian states of Jammu and Kashmir on the north, Punjab on the west and south-west, Haryana and Uttar Pradesh on the south, Uttarakhand on the south-east and by the Tibet Autonomous Region on the east...
, 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...
on 13 November 1867. This specimen (BMNH registration no. 1886.7.8. 1742) was first provisionally described as Phyllopneuste macrorhyncha (Hume
Allan Octavian Hume
Allan Octavian Hume was a civil servant, political reformer and amateur ornithologist in British India. He was one of the founders of the Indian National Congress, a political party that was later to lead the Indian independence movement...
, 1869) but the name was changed two years later to Acrocephalus macrorhynchus (Hume, 1871). H C Oberholser
Harry Church Oberholser
Harry Church Oberholser was an American ornithologist.Oberholser worked for the United States Bureau of Biological Survey from 1895 to 1941, first as an ornithologist, later as a biologist, and finally as an editor. He was the author of a number of books and articles...
however pointed out in 1905 that this was unacceptable because a specimen from Egypt described by von Müller in 1853 as Calamoherpe macrorhyncha turned out to be Acrocephalus stentoreus; Acrocephalus macrorhynchus was abandoned in favour of A. orinus. The identity of the species was in question and until 2002 was considered as a synonym of the Clamorous Reed Warbler (Acrocephalus stentoreus). Some others considered it an aberrant Blyth's Reed Warbler. A recent re-check of the morphology and the mtDNA suggested that it was a distinct species. An additional ten new specimens in collections were identified in 2008. These included specimens collected by John Biddulph
John Biddulph
Colonel John Biddulph was a British soldier, author and naturalist who served in the government of British India....
from Gilgit and W N Koelz
Walter Norman Koelz
Walter Norman Koelz was an American zoologist and museum collector.Walter Koelz's parents were immigrants from the Black Forest region of Germany, and his father was a village blacksmith in Waterloo. Walter Koelz studied zoology and received the degree of Doctor of Philosophy from the University...
from Zebak.
Rediscovery
On March 27, 2006 a living specimen was caught at the Laem Phak Bia Environmental Research and Development Project in PhetchaburiPhetchaburi Province
Phetchaburi is one of the central provinces of Thailand. Neighboring provinces are Ratchaburi, Samut Songkhram and Prachuap Khiri Khan...
, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
by ornithologist Philip Round of Mahidol University
Mahidol University
Mahidol University is a public research university in Bangkok, Thailand. Established back in 1888 as School of Medical Practitioners, Siriraj Hospital and reorganized in 1943 as University of Medical Sciences . The university originally focused on Health Sciences but also expanded to other...
. The bird was ringed
Bird ringing
Bird ringing or bird banding is a technique used in the study of wild birds, by attaching a small, individually numbered, metal or plastic tag to their legs or wings, so that various aspects of the bird's life can be studied by the ability to re-find the same individual later...
and two feathers were extracted; DNA from them was found to match the DNA of the 1867 specimen.
Based on the short and rounded wings, earlier studies had suggested that the species was likely to be a short-distant migrant or a resident. The rediscoveries of a second museum specimen from a different location and the wild specimen from Thailand suggest that this may not be so.
Some field identifications from West Bengal and central India were subsequently reported based on behaviour but captured specimens did not appear to match the species.
A breeding site of the Large-billed Reed-warbler Acrocephalus orinus, was discovered in the Wakhan Corridor
Wakhan Corridor
Wakhan Corridor is commonly used as a synonym for Wakhan, an area of far north-eastern Afghanistan which forms a land link or "corridor" between Afghanistan and China. The Corridor is a long and slender panhandle or salient, roughly long and between wide. It separates Tajikistan in the north...
of the Pamir
Pamir
Pamir may refer to:* a pamir, a U-shaped grassy valley in the Pamir Mountains**Great Pamir, a high valley in the Wakhan on the border of Afghanistan and Tajikistan**Little Pamir, a high valley in the Wakhan, Afghanistan...
of north-eastern Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...
by Researcher Robert Timmins of the Wildlife Conservation Society who was studying aviary communities in the Pamir Mountains. He came across a small brown warbler and recorded its song. Dr. Timmins did not realize the importance of his discovery until he visited a Natural History Museum in Tring, England. There he examined a specimen of a large-billed reed warbler. It was the bird he had seen and recorded.
Ornithologists verified
Verification
The word verification may refer to:* Verification and validation, in engineering or quality management systems, it is the act of reviewing, inspecting or testing, in order to establish and document that a product, service or system meets regulatory or technical standards.* Verification , in the...
his discovery by capturing and releasing almost 20 specimens of the bird in 2009, the largest number ever recorded, using a combination of field observations, museum specimens, DNA sequencing, and also the first known audio recording of the species that were already made in 2008.
A study by Russian ornithologists in 2011 indicated that the species had been misidentified as A. dumetorum in museum collections and that the species may be breeding in Tajikistan, Kyrgyzstan, eastern Uzbekistan and south-eastern Kazakhstan.