Large-billed Reed-warbler

Taxobox
name = Large-billed Reed-warbler

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image_caption = Large bill with lower mandible paler; long pointed and fanned out tail feathers; and the longer hind claw may be used to separate this from the similar "Acrocephalus dumetorum"
status = DD | status_system = IUCN3.1
status_ref = [IUCN2006
assessors= BirdLife International
year=2004
id=54296
title=Acrocephalus orinus
downloaded=6 March 2007]
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Passeriformes
familia = Sylviidae
genus = "Acrocephalus "
species = "A. orinus"
binomial = "Acrocephalus orinus"
binomial_authority = Oberholser, 1905

Large-billed Reed-warbler ("Acrocephalus orinus") is an Old World warbler in the genus "Acrocephalus". The species 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 feathers; 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. [ [http://www.birdlife.org/news/pr/2007/03/acrocephalus_orinus_rediscovered.html Birdlife International] Accessed March 2007] More recently, a warbler photographed over a few months in Kanha National Park in Central India has been identified as a Large-billed Reed-warbler. [ [http://praveenjayadevan.tripod.com/Warbler.htm Largebilled Leaf-warbler at Kanha - A sure site for a data deficient species] ]

Description

quote|The upper plumage and visible portions of wings and tail olive-brown ; the lower plumage pale ochraceous ; the under wing-coverts and axillaries paler. Length about 5 ; tail 2.3 ; wing 2.4 ; tarsus .85; bill from gape .8; the first primary measures .35 ; the second is intermediate between the ninth and tenth ; the closed tail is graduated to the extent of .4. The type specimen, the only one known, I believe, of this species is now in the British Museum. It appears to me to represent an undoubtedly distinct species of "Acrocephalus", which may be recognized by its abnormally large bill. The bird procured by Scully, and identified by him with the present species (Stray Feathers, iv, p. 146), is also in the British Museum, and is without doubt a specimen of "Tribura major". Distribution. The type was obtained in the Sutlej valley not far from Rampur.|E. W. Oates, 1889 [Oates, E. W. (1889) Fauna of British India. Birds. Volume 1.]

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 "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.

History

It was first collected by Allan Octavian Hume 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 [Hume, A. 1869. Ibis 2 (5): 355–357 (no title).] ) 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"). [Grimmett, R., Inskipp, C. & Inskipp, T. 1998. Birds of the Indian Subcontinent. London: A. & C. Black.] Some others considered it an aberrant Blyth's Reed Warbler. A recent re-check of the morphology [Vaurie, C. (1955) Systematic Notes on Palearctic Birds. No. 18:Supplementary Notes on Corvidae, Timaliinae, Alaudidae, Sylviinae, Hirundinidae, and Turdinae. American Museum Novitates. 1753 [http://digitallibrary.amnh.org/dspace/bitstream/2246/5405/1/N1753.pdf] ] and the mtDNA suggested that it was a distinct species. [Bensch, S and D. Pearson (2002) The Large-billed Reed Warbler "Acrocephalus orinus" revisited. Ibis (2002), 144:259–267 [http://ask.lub.lu.se/archive/00020515/01/Bensch_etal_Ibis_2002.pdf PDF] [http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=21396632 Nucleotide sequence] ]

Rediscovery

On March 27 2006 a living specimen was caught at the Laem Phak Bia Environmental Research and Development Project in Phetchaburi, 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. [The Nation, [http://www.nationmultimedia.com/2007/03/07/headlines/headlines_30028700.php March 6 2007] ] [Round, Philip D., Bengt Hansson, David J. Pearson, Peter R. Kennerley, Staffan Bensch. (2007) Lost and found: the enigmatic large-billed reed warbler "Acrocephalus orinus" rediscovered after 139 years. Journal of Avian Biology 38:2 133 [http://luur.lub.lu.se/luur?func=downloadFile&fileOId=624733 PDF] ]

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.

References

External links

* [http://www.ornithomedia.com/magazine/mag_art355_2.htm Identification notes]
* [http://www.nhm.ac.uk/about-us/news/2007/march/news_10987.html Natural History Museum, London]
* [http://www.orientalbirdimages.org/search.php?action=searchresult&Bird_ID=2750 Photographs]
* [http://www.kolkatabirds.com/orinus.htm Photographs from Kolkata]
* [http://www.thaibirding.com/locations/central/lpb.htm Laem Pak Bia]
** [http://www.tribuneindia.com/2007/20070413/nation.htm News reports]