White Wagtail
From Wikipedia, the free encyclopedia
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 M. alba yarrellii
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| Motacilla alba Linnaeus, 1758 |
The White Wagtail (Motacilla alba) is a small passerine in the wagtail family Motacillidae, which also includes the pipits and longclaws.
This species breeds in much of Europe and Asia and parts of north Africa. It is resident in the mildest parts of its range, but otherwise migrates to Africa. It has a toehold in Alaska as a scarce breeder.
This is an insectivorous bird of open country, often near habitation and water. It prefers bare areas for feeding, where it can see and pursue its prey. In urban areas it has adapted to foraging on paved areas such as car parks.
It nests in crevices in stone walls and similar natural and man-made structures.
This is a slender bird, 16.5-19 cm in length, with the characteristic long, constantly wagging tail of its genus. The nominate subspecies Motacilla alba alba is basically grey above and white below, with a white face, black cap and black throat.
The resident British subspecies, the (British) Pied Wagtail (M. a. yarrellii) exchanges the grey color with black (or very dark grey in females), but is otherwise identical in its behaviour.
It is likely that the differentiation of White Wagtail into two subspecies in western Europe has arisen because of the partial isolation of the mainly resident British form, although M. a. yarrellii now also breeds in adjacent areas of the neighbouring European mainland.
In addition, there are a number of other subspecies, the validity of some being questionable. They differ in the color of the wings, back, and head, with some (such as the Masked Wagtail, M. a. personata) having an all-black head with a white face mask, and the Moroccan Wagtail (M. a. subpersonata) being somewhat similar to a grey-backed white-throated African Pied Wagtail.
Several of these are occasionally proposed to constitute distinct species, for example the Black-backed Wagtail or Kamchatka/Japanese Pied Wagtail Motacilla (alba) lugens, which is essentially similar to the British birds from the opposite end of the species' range, but has a black eyestripe and white remiges. On the other hand, mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequence data (Voelker, 2002) suggests that these birds are polyphyletic or paraphyletic. While the White Wagtail appears to form a superspecies with the Japanese and White-browed Wagtails (and possibly the Mekong Wagtail, the phylogenetic position of which is mysterious), the internal systematics of the White Wagtail are still unresolved at present.
 White Wagtail (M. a. alba) |
 Pied Wagtail (M. a. yarrellii) |
 Young bird |
 Hybrid between yarrelii and alba, or a yarrelli female |
[edit] References
- BirdLife International (2006). Motacilla alba. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006.
- Voelker, Gary (2002): Systematics and historical biogeography of wagtails: Dispersal versus vicariance revisited. Condor 104(4): 725–739. [English with Spanish abstract] DOI: 10.1650/0010-5422(2002)104[0725:SAHBOW]2.0.CO;2 HTML abstract
[edit] External links
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Wikimedia Commons has media related to: |
- Internet Bird Collection: White Wagtail videos. Retrieved 2006-11-26.
- Norwegian Cyberbirding: Masked, Pied & White Wagtails photos. Retrieved 2006-11-26.
- Romani Rise: Pied Wagtail - the Gipsy Bird Pied Wagtails in Welsh Romani culture. Retrieved 2006-11-26.
