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== Taxonomía ==
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Its [[systematics]], [[phylogeny]] and [[Taxonomy (biology)|taxonomy]] are subject of considerable debate in the early 21st century. This is because this bird forms a [[cryptic species complex]] with the [[eastern yellow wagtail|eastern]] (''M. tschutschensis '') and [[western yellow wagtail]] (''M. flava''). Which of the many [[taxa]] in this group should properly refer to which [[population]] is unlikely to be resolved in the immediate future.<ref name=Voelker/>
A [[sistemática]], [[filoenia]] e [[taxonomía]] desta especie foi obxecto de considerable debate a inicios do século XXI debido a que esta ave forma un [[complexo de especies críptico]] con ''[[Motacilla tschutschensis|M. tschutschensis]]'' e ''[[Motacilla flava|M. flava]]''. Decidir cales dos moitos taxons deste grupo corresponden a cal das moitas poboacións é improbable que se resolva no futuro inmediato.<ref name=Voelker/>
''Motacilla'' is the [[Latin]] name for the pied wagtail; although actually a diminutive of ''motare'', " to move about", from medieval times it led to the misunderstanding of ''cilla'' as "tail". The specific ''citreola'' is Latin for "lemon yellow".<ref name =job>{{cite book | last= Jobling | first= James A. | year= 2010| title= The Helm Dictionary of Scientific Bird Names | publisher=Christopher Helm | location = London, United Kingdom | isbn = 978-1-4081-2501-4 | pages = 109, 261 }}</ref>
== Descrición ==
É un paxaro delgado de 15,5 a 17 cm de longo, que move constantemente súa longa cola, como é característico do xénero ''[[Motacilla]]''. O macho adulto en plumaxe reprodutora é basicamente gris ou negro por debaixo, con branco nas plumas [[rémixes]], e azul brillante por debaixo e en toda a cabeza menos na caluga negra. En pumaxe invernal, as partes amarelas poden diluírse en cor branca, e a cabeza pasa a ser amarronada con supercilio amarelado. As femias parécense xeralmente a versións destinguidas dos machos en plumaxe invernal.
It is a slender, 15.5–17 cm long bird, with the long, constantly wagging tail characteristic of the [[genus]] ''[[Motacilla]]''. The adult male in breeding plumage is basically grey or black above, with white on the [[remiges]], and bright yellow below and on the entire head except for the black nape. In winter plumage, its yellow underparts may be diluted by white, and the head is brownish with a yellowish [[supercilium]]. Females look generally like washed-out versions of males in winter plumage.
== Distribución ==
Esta especie reprodúcese na parte norte de Asia central en prados húmidos e na [[tundra]]. [[Migración das aves|migra]] en inverno ao [[sur de Asia]], a miúdo a terras altas. A súa área de distribución está expandíndose cara ao oeste e é unha ave errante rara pero cada vez máis frecuente en [[Europa]] occidental, incluíndo Galicia.<ref name=penas/> As aves errantes parecen estender a súa migración en lugar de extraviarse na súa ruta.
This species breeds in north central [[Asia]] in wet meadows and [[tundra]]. It [[bird migration|migrates]] in winter to [[South Asia]], often to highland areas. Its range is expanding westwards, and it is a rare but increasing vagrant to western [[Europe]]. Vagrants seem to extend the migration rather than straying [[wikt:en route|en route]]; in [[Bhutan]] for example, though along one of the species' migration [[flyway]]s, the citrine wagtail has been recorded as an extremely rare passer-by rather than staying even for a few days or weeks.<ref name=Inskipp/><!-- only sources Bhutan record -->
== Ecoloxía ==
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