The White wagtail is a slender bird with the characteristic long, constantly wagging tail of its genus. There are a number of other subspecies, some of which may have arisen because of partial geographical isolation, such as the resident British and Irish form, the pied wagtail M. a. yarrellii, which now also breeds in adjacent areas of the neighbouring European mainland. The Pied wagtail exchanges the grey colour of the nominate form with black (or very dark grey in females), but is otherwise identical in its behaviour. Other subspecies, the validity of some of which is questionable, differ in the colour of the wings, back, and head, or other features. Some races show sexual dimorphism during the breeding season. As many as six subspecies may be present in the wintering ground in India or Southeast Asia and here they can be difficult to distinguish.
White wagtails breed throughout Eurasia, only being absent in the Arctic. They also breed in the mountains of Morocco and western Alaska. These birds are residents in the milder parts of their range such as western Europe and the Mediterranean, but migratory in much of the rest of their range. Northern European breeders winter around the Mediterranean and in tropical and subtropical Africa, and Asiatic birds move to the Middle East, India, and Southeast Asia. Birds from the North American population also winter in tropical Asia. White wagtails occupy a wide range of habitats but are absent from deserts. They inhabit grasslands, seashores, rocky shorelines, sand beaches, tidepools, rivers, lakeshores, farmland, gardens, and parks. They are also often found in towns and villages.
Population size
135-221 Mlnlnn
Life Span
12 years
Weight
25
goz
g oz
Length
16-19
cminch
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. It has been suggested that it may flush prey, or signal submissiveness to other wagtails. A study in 2004 has suggested instead that it is a signal of vigilance to potential predators.
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. Small fish fry have also been recorded in the diet. The white wagtail is somewhat unusual in the parts of its range where it is non-migratory as it is an insectivorous bird that continues to feed on insects during the winter (most other insectivorous birds in temperate climates migrate or switch to more vegetable matter).
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