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Bristled grassbird

Bristled grassbird
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Locustellidae
Genus: Schoenicola
Species:
S. striatus
Binomial name
Schoenicola striatus
(Jerdon, 1841)[2]
Synonyms
  • Chaetornis striata (Jerdon, 1841)
  • Chaetornis striatus Sibley and Monroe (1990, 1993)
  • Dasyornis colluriceps Blyth, 1842
  • Dasyornis locustelloides Blyth, 1842
  • Megalurus striatus Jerdon, 1841[3]
  • Chaetornis striata

The bristled grassbird (Schoenicola striatus) is a small passerine bird in the genus Schoenicola. Also known as the bristled grass warbler, this species is endemic to the Indian subcontinent, where it is patchily distributed in Bangladesh, India, Nepal and Pakistan. These insectivorous birds skulk in dense and tall grasslands, often in marshy areas, habitats that are threatened by human activities. Formerly considered to be sedentary, the species may be migratory, moving south and east in the Indian peninsula during winter and returning to their breeding grounds in the northern plains south of the Himalayas.

Description

This warbler is large and brownish with broad dark streaks to the feathers of the crown and back and can appear almost babbler-like in appearance (easily mistaken for common babbler). The tail is graduated with white tips to the feathers. The rachis of the tail feathers is dark and there are dark ribs to the feathers. The bill is strong.[4] The tarsus is brown and the bill is black with the lower mandible tipped bluish grey.[5] They have a buff supercilium (brow) and have a pale unmarked underside.[6]

This species was included in the "Old World warbler" family Sylviidae, in the genus Chaetornis[7] but more comprehensive studies on external morphology and DNA sequence studies, have led to its placement in the grass warbler family Locustellidae in the genus Schoenicola as a sister species of S. platyurus.[8]

This genus in the warbler family is distinctive in having a bare patch of skin in front of the eyes (the lores) on which a vertical row of five stiff rictal bristles arise and face forward. The bare skin is flexible and it is thought that the bristles provide protection to the eye as the bird scampers between the dense and rough grass by folding back and forming a kind of cage or visor over the eye .[9] The feathers on the breast are stiff and in some individuals the tips are dark giving it a necklaced appearance. The sexes are similar in plumage.[4]

Distribution and habitat

The habitat in which the bristled grassbird occurs is tall grass-covered marshlands. The distribution range is mainly in the northern part of the Indian Subcontinent. It was formerly described as common in at least Gujarat, Andhra Pradesh, West Bengal, Orissa,[10] Lahore (where they bred in the Rakh area),[11] parts of Bangladesh, and Nepal.[12] The species is threatened by the destruction of grassland and marshland habitats. The species was thought to be mainly sedentary with movements related to the rains but they may be migratory, breeding along the riverine plains south of the Himalayas and wintering further east and south in the peninsula of India.[6][13]

Behaviour

Bristled grassbirds are hard to spot, usually seen briefly at the top of a grass clump but diving in and most often remaining hidden inside grass clumps where they forage for insect prey. Males display by rising above the grass to about a metre or so and zig-zag in the air before parachuting back down. They also call in flight with a rising and falling chwee-chew. The breeding season is from May to September and the nest is a ball of grass with an opening at the top and placed near the base of a grass clump. The usual clutch is four to five eggs, which are thought to be incubated by the female alone.[4] The eggs are white with purplish red speckles.[14]

  • Bristled grassbird (at Dadri)
    Bristled grassbird (at Dadri)
  • The bristles are thought to protect the eyes when they forage through dense grass
    The bristles are thought to protect the eyes when they forage through dense grass

References

  1. ^ BirdLife International (2017) [amended version of 2016 assessment]. "Chaetornis striata". IUCN Red List of Threatened Species. 2017: e.T22715559A111102835. doi:10.2305/IUCN.UK.2017-1.RLTS.T22715559A111102835.en. Retrieved 17 December 2023.
  2. ^ Dickinson, E.C.; Bruce, M.; Gregory, S.; Peterson, A.P.; Pittie, A. (2004). "The dating of names proposed in the first Supplement to Thomas Jerdon's Catalogue of the birds of the peninsula of India". The Bulletin of Zoological Nomenclature. 61: 214–221.
  3. ^ Jerdon, T.C. (1863). The Birds of India. Volume 2. Part 1. Calcutta: Military Orphan Press. pp. 72–73.
  4. ^ a b c d Ali, S.; Ripley, S. D. (1997). Handbook of the Birds of India and Pakistan. volume 8 (2nd ed.). New Delhi: Oxford University Press. pp. 93–94.
  5. ^ Oates, Eugene W. (1889). The Fauna of British India, including Ceylon and Burma. Birds. Volume 1. London: Taylor and Francis. pp. 387–389.
  6. ^ a b c Rasmussen, P.C.; Anderton, J.C. (2005). Birds of South Asia. Volume 2. pp. 515–516.
  7. ^ Drovetski, S. V.; m. Zink, R. M.; v. Fadeev, I. V.; v. Nesterov, E. V.; a. Koblik, E. A.; a. Red'Kin, Y. A.; Rohwer, S. (2004). "Mitochondrial phylogeny of Locustella and related genera". J. Avian Biol. 35 (2): 105–110. doi:10.1111/j.0908-8857.2004.03217.x.
  8. ^ Alström, Per; Cibois, Alice; Irestedt, Martin; Zuccon, Dario; Gelang, Magnus; Fjeldså, Jon; Andersen, Michael J.; Moyle, Robert G.; Pasquet, Eric (2018). "Comprehensive molecular phylogeny of the grassbirds and allies (Locustellidae) reveals extensive non-monophyly of traditional genera, and a proposal for a new classification". Molecular Phylogenetics and Evolution. 127: 367–375. doi:10.1016/j.ympev.2018.03.029. ISSN 1055-7903. PMID 29625229.
  9. ^ Whistler, Hugh (1929). "The study of Indian birds. Part III. Some external characteristics of birds". J. Bombay Nat. Hist. Soc. 33 (4): 776–792.
  10. ^ Ball, Valentine (1876). "Notes on some birds collected at Sambalpur and Orissa". Stray Feathers. 4: 231–237.
  11. ^ Currie, A.J. (1916). "The occurrence of the Bristled Grass-Warbler Chaetornis locustelloides at Lahore". J. Bombay Nat. Hist. Soc. 24 (3): 593–594.
  12. ^ Heath, P.J.; Thorns, D.M. (1989). "Bristled Grass Warbler Chaetornis striatus new to and breeding in Nepal, and its separation from Large Grass Warbler Graminicola bengalensis". Forktail. 4: 118–121.
  13. ^ Butler, E.A. (1877). "The Avifauna of Mount Aboo and North Gujerat". Stray Feathers. 5: 207–236.
  14. ^ Baker, E.C.S. Fauna of British India, including Ceylon and Burma. Birds. Volume 2 (2nd ed.). London: Taylor and Francis. pp. 438–439.
Quelle: http://en.wikipedia.org/wiki/Bristled_grassbird