تصویر 35 - دم جنبانک ابلق
تصویر 35 - دم جنبانک ابلق
"Pied Wagtail" redirects here. For the related African bird, see African Pied Wagtail.
The
White Wagtail (
Motacilla alba) is a small
passerine bird 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. In the British Isles the darker sub-species the
Pied Wagtail (
M. a. yarrellii) predominates.
The White Wagtail 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.
The White Wagtail is the national bird of
Latvia.[SUP]
[2][/SUP]
[h=2][
edit] Taxonomy and systematics[/h]
Breeding ranges of the major races
The White Wagtail was one of the many species originally described by
Linnaeus in his 18th century work,
Systema Naturae, and it still bears its original name of
Motacilla alba.[SUP]
[3][/SUP] The
Latin genus name originally meant "little mover", but certain
medieval writers thought it meant "wag-tail", giving rise to a new Latin word
cilla for "tail".[SUP]
[4][/SUP] The specific epithet
alba is Latin for "white".
Within the wagtail genus
Motacilla, the White Wagtail's closest relatives appear to be other black-and-white wagtails such as the
Japanese Wagtail,
Motacilla grandis, and the
White-browed Wagtail,
Motacilla madaraspatensis (and possibly the
Mekong Wagtail,
Motacilla samveasnae, the
phylogenetic position of which is mysterious), with which it appears to form a
superspecies. However,
mtDNA cytochrome b and
NADH dehydrogenase subunit 2
sequence data suggests that the White Wagtail is itself
polyphyletic or
paraphyletic (i.e. the species is not itself a single coherent grouping).[SUP]
[5][/SUP] Other phylogenetic studies using mtDNA still suggest that there is considerable gene flow within the races and the resulting closeness makes
Motacilla alba a single species.[SUP]
[6][/SUP] Some studies have suggested the existence of only two groups : the
alboides group, with
M. a. alboides,
M. a. leucopsis and
M. a. personata; and the
alba group, with
M. a. alba,
M. a. yarrellii,
M. a. baicalensis,
M. a. ocularis,
M. a. lugens, and
M. a. subpersonata.[SUP]
[7][/SUP]
[h=2][
edit] Description[/h] The White Wagtail is a slender bird, 16.5–19 cm (6½–7½ in) in length (East Asian subspecies are longer, measuring up to 21 cm (8¼ in), with the characteristic long, constantly wagging tail of its genus. Its average weight is 25 g (0.88 oz) and the maximum lifespan in the wild is ca. 12 years.[SUP]
[8][/SUP] The
nominate subspecies Motacilla alba alba is basically grey above and white below, with a white face, black cap and black throat.
There are a number of other subspecies, some of which may have arisen because of partial geographical isolation, such as the resident British form, the Pied Wagtail
M. a. yarrellii, which now also breeds in adjacent areas of the neighbouring European mainland. The Pied Wagtail, named for naturalist
William Yarrell, 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
***ual 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.[SUP]
[9][/SUP][SUP]
[10][/SUP][SUP]
[11][/SUP][SUP]
[12][/SUP] Phylogenetic studies using mtDNA suggest that some morphological features have evolved more than once, including the back and chin colour. Breeding
M. a. yarrellii look much like the nominate race except for the black back, and
M. a. alboides of the Himalayas differs from the Central Asian
M. a. personata only by its black back.
M. a. personata has been recorded breeding in the Siddar Valley of Kashmir of the Western Himalayas.[SUP]
[13][/SUP] It has also been noted that both back and chin change colour during the
pre-basic moult; all black-throated subspecies develop white chins and throats in winter and some black-backed birds are grey-backed in winter.[SUP]
[6][/SUP][SUP]
[9][/SUP]
The call of the White Wagtail is a sharp
chisick, slightly softer than the version given by the Pied Wagtail. The song is a pleasant twittering, more regular in White than Pied, but with little territorial significance, since the male uses a series of contact calls to attract the female.[SUP]
[14][/SUP]
[h=3][
edit] Subspecies[/h] Nine or eleven subspecies are currently recognised. Information on the plumage differences and distribution of the subspecies of the White Wagtail is shown below.[SUP]
[15][/SUP]
| Subspecies | Range | Notes | Image |
|---|
| M. a. alba | Europe from the Iberian Peninsula to Ural Mountains, Turkey, the Levant, Iceland, the Faroe Islands and Greenland's east coast. Some migrate to the south of Europe and Africa down as far as Kenya and Malawi | Nominate subspecies |
|
| M. a. yarrellii | Great Britain and Ireland, birds in the northern part of the range winter in Spain and North Africa, those further south are resident.[SUP][16][/SUP] | Pied Wagtail. Has a much blacker back than the nominate race, black of throat continues on side of neck |
|
| M. a. dukhunensis | West Siberian Plain – east Caspian Sea (part of Russia, Kazakhstan, Uzbekistan, Turkmenistan), winters in the Middle East and India. Sometimes included in alba.[SUP][16][/SUP] | Indian Pied Wagtail. The upperparts of this subspecies are paler and more blue-grey than nominate, and has it has a continuous unbroken white panel on wing coverts. | |
| M. a. persica | North central and western Iran. | Intermediate between M. a. dukhunensis and M. a. personata. Often included in alba; appears to be hybrid or intergrade population.[SUP][16][/SUP] |
|
| M. a. subpersonata | Non-migratory resident of Morocco | Moroccan Wagtail. It has more black on the head than the nominate, and resembles a grey-backed, white-throated African Pied Wagtail[SUP][16][/SUP] | |
| M. a. personata | Hindu Kush, Tian Shan, Altay Mountains (northern Iran, Afghanistan, Tajikistan, Kyrgyzstan, Kazakhstan, Xinjiang) | Masked Wagtail. All-black head with a white face mask |
|
| M. a. alboides | Himalayas and surrounding area | This subspecies has a black back and a lot of black around the head, a white wing panel and white edges on the secondaries and tertials. | |
| M. a. baicalensis | Russia in Lake Baikal area, Mongolia, Inner Mongolia | Resembles M. a. leucopsis but grey back and less white on head and wing. | |
| M. a. ocularis | Siberia, Far Eastern (Russia, eastwards from Central Siberian Plateau) expanding into West Alaska | | |
| M. a. lugens | Russia Far East (Primorsky Krai, Khabarovsk Krai), Kamchatka Peninsula, Kuril Islands, Sakhalin, Japan (Hokkaidō, Honshū) | Black-backed Wagtail or Kamchatka/Japanese Pied Wagtail, similar to M. a. yarrellii, but has a black eyestripe and white remiges; might have a claim to constitute a distinct species. |
|
| M. a. leucopsis | China, Korean Peninsula, Taiwan, Japan (Ryukyu Islands, Kyūshū) expanding into Japan (Honshū), Southeast Asia, India and Oceania
| Amur Wagtail[SUP][17][/SUP][SUP][18][/SUP][SUP][19][/SUP] |
|
[h=2][
edit] Distribution and habitat[/h]
Worldwide distribution of the White Wagtail. Yellow denotes summer range, green year round range, blue winter range.
This species breeds throughout Eurasia up to latitudes 75°N, only being absent in the
Arctic from areas where the July isotherm is less than 4 °C. It also breeds in the mountains of
Morocco and western
Alaska. It occupies a wide range of habitats, but is absent from deserts.[SUP]
[14][/SUP]
White Wagtail is resident in the milder parts of its range such as western Europe and the
Mediterranean, but
migratory in much of the rest of its range. Northern European breeders winter around the Mediterranean and in tropical and subtropical
Africa,[SUP]
[20][/SUP] and Asiatic birds move to the
Middle East,
India,[SUP]
[16][/SUP] and
SouthEast Asia.[SUP]
[21][/SUP] Birds from the North American population also winter in tropical Asia.[SUP]
[22][/SUP]
[h=2][
edit] Behaviour and ecology[/h] 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 recent study has suggested instead that it is a signal of vigilance to potential predators.[SUP]
[23][/SUP]
[h=3][
edit] Diet and feeding[/h] 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 in the order Diptera.[SUP]
[16][/SUP] Small fish fry have also been recorded in the diet. The White Wagtail is somewhat unusual in the parts of it 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).[SUP]
[24][/SUP]
[h=3][
edit] Breeding[/h]
A juvenile
M. a. yarrellii in England. It has a grey face and grey area on its chest
Juvenile
M. a. alba in northern Norway, showing the grey face and chest
White Wagtails are
monogamous and defend breeding
territories.[SUP]
[16][/SUP] The breeding season for most is from April to August, with the season starting later further north. Both ***es are responsible for building the
nest, with the male responsible for initiating the nest building and the female for finishing the process. For second broods in the subspecies
personata the female alone builds the nest as the male is still provisioning the young.[SUP]
[25][/SUP] which is a rough cup assembled from twigs, grass, leaves and other plant matter. It is lined with soft materials, including animal hair. The nest is set into a crevice or hole; traditionally in a bank next to a river or ditch, but the species has also adapted to nesting in walls, bridges and buildings. One nest was found in the skull of a walrus. They species will nest in association with other animals, particularly where available the dams of
beavers and also inside the nests of
Golden Eagles.[SUP]
[25][/SUP] Around 3–8 eggs are laid, with the usual number being 4–6. Its
eggs are cream-coloured, often with a faint bluish-green or turquoise tint, and heavily spotted with reddish brown; they measure, on average, 21×15 mm (0.83×0.59 inches).[SUP]
[26][/SUP] Both parents
incubate the eggs, although the female generally does so for longer and incubates at night. The eggs begin to hatch after 12 days (sometimes as late as 16 days). Both parents feed the chicks until they
fledge at around 14 days, and the chicks are fed for another week after fledging.
Though it is known to be a host species for the
Common Cuckoo, the White Wagtail typically deserts its nest if it has been parasitised. Scientists theorise that this occurs because the wagtail is too small to push the intruding egg out of the nest, and too short-billed to destroy the egg by puncturing it.[SUP]
[27][/SUP]
[h=2][
edit] Status[/h] This species has a large range, with an estimated extent of more than 10 million km² (3.8 sq mi). The population size is unknown, but it is believed to be large, as the species is described as "common" in at least parts of its range. Population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.[SUP]
[1][/SUP] The population in Europe appears to be stable.[SUP]
[20][/SUP] The species has adapted well to human changes to the environment, and has in fact exploited human changes such as man-made structures which are used for nesting sites and increased open areas which are used for foraging.[SUP]
[16][/SUP] In a number of cities, notably
Dublin, large flocks gather in winter to roost
