|বগা বালিমাহী (White Wagtail)|
|M. alba alba|
|গণ:|| Motacilla |
বগা বালিমাহী, (ইংৰাজী: White Wagtail, বৈজ্ঞানিক নাম-Motacilla alba) এটা সৰু আকাৰৰ বালিমাহী চৰাইৰ প্ৰজাতি৷ ই ঘাইকৈ ইউৰোপ, এছিয়া আৰু উত্তৰ আফ্ৰিকাত প্ৰজনন কৰে৷ বগা বালিমাহী পতংগভোজী৷ ইহঁতে প্ৰধানকৈ জলাশয় বা পানীৰ অন্যান্য উৎসৰ আশে পাশে চৰে৷
The White Wagtail is a slender bird, 16.5–19 cm (6½–7½ in) in length (East Asian subspecies are longer, measuring up to 21 cm (8¼ in), with the characteristic long, constantly wagging tail of its genus. Its average weight is 25 g (0.88 oz) and the maximum lifespan in the wild is ca. 12 years. The nominate subspecies Motacilla alba alba is basically grey above and white below, with a white face, black cap and black throat. he call of the White Wagtail is a sharp chisick, slightly softer than the version given by the Pied Wagtail. The song is a pleasant twittering, more regular in White than Pied, but with little territorial significance, since the male uses a series of contact calls to attract the female.
Nine or eleven subspecies are currently recognised. Information on the plumage differences and distribution of the subspecies of the White Wagtail is shown below.
|M. a. alba||Europe from the Iberian Peninsula to Ural Mountains, Turkey, the Levant, Iceland, the Faroe Islands and Greenland's east coast. Some migrate to the south of Europe and Africa down as far as Kenya and Malawi||Nominate subspecies|
|M. a. yarrellii||Great Britain and Ireland, birds in the northern part of the range winter in Spain and North Africa, those further south are resident.||Pied Wagtail. Has a much blacker back than the nominate race, black of throat continues on side of neck|
|M. a. dukhunensis||West Siberian Plain – east Caspian Sea (part of Russia, Kazakhstan, Uzbekistan, Turkmenistan), winters in the Middle East and India. Sometimes included in alba.||Indian Pied Wagtail. The upperparts of this subspecies are paler and more blue-grey than nominate, and has it has a continuous unbroken white panel on wing coverts.|
|M. a. persica||North central and western Iran.||Intermediate between M. a. dukhunensis and M. a. personata. Often included in alba; appears to be hybrid or intergrade population.|
|M. a. subpersonata||Non-migratory resident of Morocco||Moroccan Wagtail. It has more black on the head than the nominate, and resembles a grey-backed, white-throated African Pied Wagtail|
|M. a. personata||Hindu Kush, Tian Shan, Altay Mountains (northern Iran, Afghanistan, Tajikistan, Kyrgyzstan, Kazakhstan, Xinjiang)||Masked Wagtail. All-black head with a white face mask|
|M. a. alboides||Himalayas and surrounding area||This subspecies has a black back and a lot of black around the head, a white wing panel and white edges on the secondaries and tertials.|
|M. a. baicalensis||Russia in Lake Baikal area, Mongolia, Inner Mongolia||Resembles M. a. leucopsis but grey back and less white on head and wing.|
|M. a. ocularis||Siberia, Far Eastern (Russia, eastwards from Central Siberian Plateau) expanding into West Alaska|
|M. a. lugens||Russia Far East (Primorsky Krai, Khabarovsk Krai), Kamchatka Peninsula, Kuril Islands, Sakhalin, Japan (Hokkaidō, Honshū)||Black-backed Wagtail or Kamchatka/Japanese Pied Wagtail, similar to M. a. yarrellii, but has a black eyestripe and white remiges; might have a claim to constitute a distinct species.|
|M. a. leucopsis||China, Korean Peninsula, Taiwan, Japan (Ryukyu Islands, Kyūshū)||Amur Wagtail|
This species breeds throughout Eurasia up to latitudes 75°N, only being absent in the Arctic from areas where the July isotherm is less than 4 °C. It also breeds in the mountains of Morocco and western Alaska.
It occupies a wide range of habitats, but is absent from deserts.
The most conspicuous habit of this species is a near-constant tail wagging, a trait that has given the species, and indeed the genus, its common name. In spite of the ubiquity of this behaviour, the reasons for it are poorly understood. 
The exact composition of the diet of White Wagtails varies by location, but terrestrial and aquatic insects and other small invertebrates form the major part of the diet. These range from beetles, dragonflies, small snails, spiders, worms, crustaceans, to maggots found in carcasses and, most importantly, flies in the order Diptera. Small fish fry have also been recorded in the diet. 
White Wagtails are monogamous and defend breeding territories. The breeding season for most is from April to August, with the season starting later further north. Both sexes are responsible for building the nest, with the male responsible for initiating the nest building and the female for finishing the process. The nest is set into a crevice or hole; traditionally in a bank next to a river or ditch, but the species has also adapted to nesting in walls, bridges and buildings. One nest was found in the skull of a walrus. They species will nest in association with other animals, particularly where available the dams of beavers and also inside the nests of Golden Eagles. Around 3–8 eggs are laid, with the usual number being 4–6. Its eggs are cream-coloured, often with a faint bluish-green or turquoise tint, and heavily spotted with reddish brown; they measure, on average, 21×15 mm (0.83×0.59 inches). Both parents incubate the eggs, although the female generally does so for longer and incubates at night. The eggs begin to hatch after 12 days (sometimes as late as 16 days). Both parents feed the chicks until they fledge at around 14 days, and the chicks are fed for another week after fledging.
This species has a large range, with an estimated extent of more than 10 million km² (3.8 sq mi). The population size is unknown, but it is believed to be large, as the species is described as "common" in at least parts of its range. Population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. The population in Europe appears to be stable.
আলোকচিত্ৰৰ ভঁৰাল[সম্পাদনা কৰক]
- BirdLife International (2012). "Motacilla alba". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/106008403। আহৰণ কৰা হৈছে: 16 July 2012.
- Simms, Eric (Author); Arlott, Norman (Illustrator) (1992). Larks, Pipits and Wagtails (Collins New Naturalist). Harper Collins. পৃষ্ঠা. 233–252. ISBN 000219871.
- সাঁচ:Ja icon Nakamura, Kazue (1985). "Historical change of the geographical distribution of two closely related species of the genus Motacilla in the Japanese Archipelago: a preliminary note". Bulletin of the Kanagawa prefecture Museum of Natural Science খণ্ড 16.
- Tyler, S. (2004) "Family Motacillidae (Pipits and Wagtails)" pp.777–778 in del Hoyo, J.; Elliot, A. & Christie D. (editors). (2004). Handbook of the Birds of the World. Volume 9: Cotingas to Pipits and Wagtails. Lynx Edicions. ISBN 84-87334-69-5
- British Ornithologists’ Union Records Committee; British Birds Rarities Committee (22 July 2009). "Changes to Category A of the British List". BOU News. British Ornithologists’ Union. http://bou-news.blogspot.com/2010/09/changes-to-category-of-british-list.html। আহৰণ কৰা হৈছে: 22 July 2009.
- Addinall, Stephen (May 2010). "'Amur Wagtail' in County Durham: new to Britain and the Western Palearctic". British Birds খণ্ড 103: 260–267. http://www.birdingworld.co.uk/images/AmurWagtail.pdf.
- Rowlands, Adam (May 2010). "Proposed criteria for BBRC assessment of claims of 'Amur Wagtail'". British Birds খণ্ড 103: 268–275.
- Randler, C (2006). "Is tail wagging in white wagtails, Motacilla alba, an honest signal of vigilance?" Animal Behaviour 71 (5): 1089–1093 Abstract
- Davies, N.B. (1976). "Food, Flocking and Territorial Behaviour of the Pied Wagtail (Motacilla alba yarrellii Gould) in Winter". The Journal of Animal Ecology খণ্ড 45 (1): 235–253. doi:10.2307/3777.
- Badyaev, A. V.; Gibson, D. D. and Kessel, B. (1996). "White Wagtail (Moticilla alba)". The Birds of North America Online. Ithaca: Cornell Lab of Ornithology. doi:10.2173/bna.236. http://bna.birds.cornell.edu/bna/species/236। আহৰণ কৰা হৈছে: 16 April 2010.
- Peyton, Leonard J. (May 1963). "Nesting and occurrence of White Wagtail in Alaska" (PDF). Condor খণ্ড 65 (3): 232–235. doi:10.2307/1365667. http://sora.unm.edu/sites/default/files/journals/condor/v065n03/p0232-p0235.pdf.
- উদ্ধৃতি ত্ৰুটি: অবৈধ
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বাহ্যিক সংযোগ[সম্পাদনা কৰক]
|ৱিকিমিডিয়া কমন্সত বগা বালিমাহী সম্পৰ্কীয় মিডিয়া ফাইল আছে।|
|ৱিকিপ্ৰজাতিত Motacilla alba সম্পৰ্কে অধিক তথ্য আছে|
- Wagtail videos, photos & sounds on the Internet Bird Collection
- Norwegian Cyberbirding: Masked, Pied & White Wagtails photos.
- Romani Rise: Pied Wagtail – the Gipsy Bird Pied Wagtails in Welsh Romani culture
- Identification article with pictures (PDF)
- Ageing and sexing (PDF; 4.9 MB) by Javier Blasco-Zumeta & Gerd-Michael Heinze