White Wagtail

The white wagtail (Motacilla alba) is a slender, long-tailed songbird found across a vast area from Europe and North Africa through most of Asia. Adults are about 16.5–19 cm long and weigh around 23 g on average. The plumage is strongly contrasting black, white and grey, with a white face, dark crown and throat, grey or blackish upperparts and white underparts. The long black-and-white tail is almost constantly moved up and down while the bird walks or runs.

Plumage varies geographically. The nominate white wagtail M. a. alba has a grey back and breeds across much of continental Europe, whereas the British and Irish pied wagtail M. a. yarrellii is much darker-backed. Farther east, forms such as the masked wagtail M. a. personata have much more extensive black on the head and face. Several other geographical forms occur across Asia, producing striking variation in the distribution of black, grey and white across the species’ enormous range.

White wagtails favour open ground where small prey is easy to see and catch. Riverbanks, lake shores, coastlines, farmland, short grass, roadsides, villages, industrial areas, parks and high mountain settlements can all be suitable.

Water is common in their habitat but is not essential. The key combination is usually an open feeding surface with nearby perches and sheltered nesting sites, which helps explain why the species adapts so readily to farms, towns and other human-modified landscapes.

The diet consists mainly of insects and other small invertebrates, both terrestrial and aquatic. Birds walk and run rapidly across open ground, stopping to pick prey from the surface or making short aerial sallies after flying insects.

This active ground-foraging style allows the wagtail to exploit prey exposed on short grass, bare soil, shorelines and paved surfaces. Feeding birds frequently change direction and accelerate after moving insects rather than remaining at one fixed feeding point.

The repeated up-and-down movement of the tail is the wagtail’s most characteristic behaviour, but its exact function is still debated. It has long been suggested that wagging might flush small invertebrates into movement and make them easier to detect, while other explanations involve social signalling or alertness.

A study published in 2006 found that white wagtails wagged not only while feeding but also while preening. Wagging became more frequent when birds scanned their surroundings and less frequent while they were actually pecking at food. This makes a purely prey-flushing explanation less convincing and fits better with tail wagging as a visible signal of vigilance. The behaviour may therefore advertise that a bird is alert rather than serving only as a mechanical feeding aid.

Migration varies greatly across the range. Populations in northern and eastern Eurasia are strongly migratory and move south to milder parts of Europe, Africa and southern Asia for winter, while many birds in western and southern Europe are resident or make only shorter movements.

Migrants can gather in loose feeding flocks and at communal roosts during passage and in winter. The dark-backed pied wagtail of Britain and Ireland is much more sedentary than many populations of the nominate white wagtail, although some individuals also make seasonal movements into continental Europe.

White wagtails usually nest in sheltered cavities or recesses rather than building exposed nests. Natural holes in rocks and banks are used, but buildings, bridges, walls, roofs and other structures are now extremely common nest sites. Both members of the pair contribute to building a nest of grass, roots, moss and other plant material with a softer lining.

A typical clutch contains 5–6 eggs. The female performs the incubation, which normally lasts about 13 days, while both parents feed the young after hatching. The chicks usually remain in the nest for about 14–15 days before fledging. Two broods are typical in favourable parts of the range.

The white wagtail is classified as least concern on the IUCN Red List. Its enormous Eurasian range and broad tolerance of both natural and human-modified habitats make the species globally secure, and the global population trend is considered stable.

Regional populations nevertheless follow different trajectories, with declines in some areas despite the species remaining common and widespread overall.