Motacilla alba yarrellii, commonly known as the pied wagtail or Yarrell's wagtail, is a small black, white, and grey passerine bird. It is a well-known subspecies of the white wagtail (Motacilla alba) that primarily breeds in Great Britain and Ireland.
The pied wagtail (Motacilla alba yarrellii) is a small, active black-and-white bird measuring about 18 cm long and weighing 17–25g. Famous for constantly pumping its long tail up and down, it is a common, year-round resident across Ireland and Britain, frequently found dashing across lawns, car parks, and urban areas.

Physical Traits
Appearance: Features a striking black back, a black crown and bib, contrasting white cheeks, and a bright white belly. Females often have a slightly greyer back than males.
Tail: Possesses a long, narrow black-and-white tail that is constantly pumped or "wagged" up and down.
Size: Measures about 16 to 19 cm in length with a wingspan of 25 to 30 cm, weighing roughly 17 to 28 grams.
Habitat and Behavior
Diet: Primarily feeds on insects, including flies, beetles, and caterpillars, running swiftly across open ground to catch prey.
Urban Adaptation: Highly comfortable around humans, frequently seen darting across lawns, paved carparks, and suburban rooftops.
Nesting: Builds nests in natural and artificial crevices, such as stone walls, rock faces, and building cavities.
Distribution and Migration
Range: Resident across much of Britain and Ireland. Birds in northern populations are migratory, moving south into Spain and North Africa for the winter, while southern populations tend to stay put year-round.
Roosting: Gathers in large communal winter roosts in city centers on buildings or in trees to stay warm.
Physical Traits and Identification
Plumage: Striking black-and-white design with a white face, black crown and back, and a white belly.
Flight: Distinctly undulating flight pattern, bouncing up and down through the air.
Lifespan: Typically lives for 2 years, though the oldest recorded wild individual lived over 11 years.