Wagtails are a group of

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by t ...

birds that form the genus ''Motacilla'' in the family

Motacillidae The wagtails, longclaws, and pipits are a family, Motacillidae, of small passerine birds with medium to long tails. Around 70 species occur in five genera. The longclaws are entirely restricted to the Afrotropics, and the wagtails are predominan ...

. The

forest wagtail The forest wagtail (''Dendronanthus indicus'') is a medium-sized passerine bird in the wagtail family Motacillidae. It has a distinctive plumage that sets it apart from other wagtails and has the habit of wagging its tail sideways unlike the usua ...

belongs to the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Dendronanthus'' which is closely related to ''Motacilla'' and sometimes included therein. The common name and genus names are derived from their characteristic tail pumping behaviour. Together with the

pipit The pipits are a Cosmopolitan distribution, cosmopolitan genus, ''Anthus'', of small passerine birds with medium to long tails. Along with the wagtails and longclaws, the pipits make up the family (biology), family Motacillidae. The genus is wide ...

s and

longclaw The longclaws are a genus, ''Macronyx'', of small African passerine birds in the family Motacillidae. Longclaws are slender, often colorful, ground-feeding insectivores of open country. They are ground nesters, laying up to four speckled eggs. T ...

s they form the family

The

willie wagtail The willy (or willie) wagtail (''Rhipidura leucophrys'') is a passerine bird native to Australia, New Guinea, the Solomon Islands, the Bismarck Archipelago, and Eastern Indonesia. It is a common and familiar bird throughout much of its range, ...

(''Rhipidura leucophrys'') of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

is an unrelated bird similar in coloration and shape to the

Japanese wagtail The Japanese wagtail (''Motacilla grandis'') is a species of bird in the pipit and wagtail family Motacillidae. It is native to Japan and Korea. Description The Japanese wagtail is about 20 cm long. The sexes look similar; they have white ...

. It belongs to the

fantail Fantails are small insectivorous songbirds of the genus ''Rhipidura'' in the family Rhipiduridae, native to Australasia, Southeast Asia and the Indian subcontinent. Most of the species are about long, specialist aerial feeders, and named as "f ...

Taxonomy

The genus ''Motacilla'' was introduced by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758 in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

''. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is the

white wagtail The white wagtail (''Motacilla alba'') is a small passerine bird in the family Motacillidae, which also includes pipits and longclaws. The species breeds in much of Europe and the Asian Palearctic and parts of North Africa. It has a toehold in ...

. ''Motacilla'' is the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

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". At first glance, the wagtails appear to be divided into a yellow-bellied group and a white-bellied one, or one where the upper head is black and another where it is usually grey, but may be olive, yellow, or other colours. However, these are not

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

ary lineages; change of belly colour and increase of

melanin Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino ...

have occurred independently several times in the wagtails, and the colour patterns which actually indicate relationships are more subtle.

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

cytochrome ''b'' and

NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the for ...

subunit 2

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

data (Voelker, 2002) is of limited use: the suspicion that there is a superspecies of probably three white-bellied, black-throated wagtails is confirmed. Also, there is another superspecies in

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

, three white-throated species with a black breast-band. The remaining five species are highly variable morphologically and their relationships with each other and with the two

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s have not yet been satisfactorily explained. The origin of the genus appears to be in the general area of Eastern

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

/Mongolia. Wagtails spread rapidly across Eurasia and dispersed to

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

in the

Zanclean The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and fol ...

(Early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58African pied wagtail (and possibly the

Mekong wagtail The Mekong wagtail (''Motacilla samveasnae'') is a species of bird in the family Motacillidae. It was first described in 2001 and named in honour of the late Cambodian ornithologist Sam Veasna. It is a black and white bird, similar in appearance ...

) diverged prior to the massive radiation of the white-bellied black-throated and most yellow-bellied forms, all of which took place during the late

Piacenzian The Piacenzian is in the international geologic time scale the upper stage (stratigraphy), stage or latest age (geology), age of the Pliocene. It spans the time between 3.6 ± 0.005 year#SI prefix multipliers, Ma and 2.588 ± 0.005 Ma (million yea ...

(early Late Pliocene), c. 3 mya. Three species are poly- or paraphyletic in the present

taxonomical In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given ...

arrangement and either

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

need to be reassigned and/or species split up. The blue-headed wagtail (AKA yellow wagtail and many other names), especially, has always been a taxonomical nightmare with over a dozen currently accepted subspecies and many more invalid ones. The two remaining "

monochrome A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochrom ...

" species,

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's List of rivers by length, twelfth longest river and List of longest rivers of Asia, the third longest in Asia. Its estimated length is , ...

and African pied wagtail may be closely related, or a most striking example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

. Prehistoric wagtails known from

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

are ''Motacilla humata'' and ''Motacilla major''.

Characteristics

Wagtails are slender, often colourful, ground-feeding

insectivore A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores wer ...

s of open country in the

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...

. Species of wagtail breed in Africa, Europe and Asia, some of which are fully or partially migratory. Two species also breed in Alaska, and wintering birds may reach Australia. They are ground nesters, laying up to six speckled

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s at a time. Among their most conspicuous behaviours is a near constant tail wagging, a trait that has given the birds their common name. In spite of the ubiquity of the behaviour and observations of it, the reasons for it are poorly understood. It has been suggested that it may flush up prey, or that it may signal submissiveness to other wagtails. Recent studies have suggested instead that it is a signal of vigilance that may aid to deter potential predators.

Species list

The genus contains 13 species.

Former species in this genus

Formerly, some authorities also considered the following species (or subspecies) as species within the genus ''Motacilla'': *

Superb fairywren The superb fairywren (''Malurus cyaneus'') is a passerine bird in the Australasian wren family, Maluridae, and is common and familiar across south-eastern Australia. It is a sedentary and territorial species, also exhibiting a high degree of se ...

(as ''Motacilla cyanea'') * Red-whiskered bulbul (emeria) (as ''Motacilla emeria'')

References

Sources

* Voelker, Gary (2002)
"Systematics and historical biogeography of wagtails: Dispersal versus vicariance revisited"
''

Condor Condor is the common name for two species of New World vultures, each in a monotypic genus. The name derives from the Quechua ''kuntur''. They are the largest flying land birds in the Western Hemisphere. They are: * The Andean condor (''Vult ...

'' 104(4): 725–739. nglish with Spanish abstract DOI: 10.1650/0010-5422(2002)104 725:SAHBOW.0.CO;2
HTML abstract

External links

*
Wagtail videos
on the Internet Bird Collection {{Taxonbar, from=Q230042 * Taxa named by Carl Linnaeus