The Willow Warbler is a very common and widespread leaf warbler

Leaf warbler

Leaf-warblers are small insectivorous birds belonging mainly to the genus Phylloscopus. They were formerly included in the Old World warbler family but are now considered to belong to the Phylloscopidae, a family created in 2006. The genus is closely related to Seicercus and some species have been...

 which breeds throughout northern and temperate Europe and Asia, from Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 east to the Anadyr River

Anadyr River

Anadyr is a river in the far northeast Siberia which flows into Anadyr Bay of the Bering Sea and drains much of the interior of Chukotka Autonomous Okrug. Its basin corresponds to the Anadyrsky District of Chukotka....

 basin in eastern Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

. It is strongly migratory

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

, with almost all of the population wintering in sub-Saharan Africa.

It is a bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 of open woodlands with trees and ground cover for nesting, including most importantly birch

Birch

Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...

, alder

Alder

Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

, and willow

Willow

Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

 habitats. The nest is usually built in close contact with the ground, often in low vegetation. Like most Old World warblers, this small passerine

Passerine

A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...

 is insectivorous. In northern Europe, it is one of the first warbler

Warbler

There are a number of Passeriformes called "warblers". They are not particularly closely related, but share some characteristics, such as being fairly small, vocal and insectivorous....

s to return in the spring though is later than the closely related Chiffchaff

Chiffchaff

The Common Chiffchaff, or simply the Chiffchaff, is a common and widespread leaf-warbler which breeds in open woodlands throughout northern and temperate Europe and Asia....

 Phylloscopus collybita.

Description

It is a typical leaf warbler in appearance, 11–12.5 cm long and 7–15 g weight. It is greenish brown above and off-white to yellowish below; the wings are plain greenish-brown with no wingbars. Juveniles are yellower below than adults. It is very similar to the Chiffchaff, but non-singing birds can be distinguished from that species by their paler pinkish-yellow legs (dark brown to blackish in Chiffchaff), longer paler bill, more elegant shape and longer primary projection (wingtip). Its song is a simple repetitive descending whistle, while the contact call is a disyllabic 'hoo-eet', distinct from the more monosyllabic 'hweet' of Chiffchaffs.

Subspecies

Three subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 are accepted, with a partly clinal reduction in green and yellow plumage tones from west to east, with central birds browner and easternmost birds predominantly greyish:

• Phylloscopus trochilus trochilus (Linnaeus, 1758). Breeds Europe (from the Pyrenees and Alps northward) except northern Scandinavia, winters west Africa.
• Phylloscopus trochilus acredula (Linnaeus, 1758). Breeds northern Scandinavia east to western Siberia, winters central Africa.
• Phylloscopus trochilus yakutensis Ticehurst, 1935. Breeds eastern Siberia, winters eastern and southern Africa.

Behaviour

All populations are highly migratory, with the subspecies P. t. yakutensis migrating up to 12,000 km from eastern Siberia to southern Africa, one of the longest migrations of any for a bird of its size. Approximate timings are:

• October to March: wintering in sub Saharan Africa.
• Mid March to mid May: migrates and arrives in the breeding range.
• Late April to August: breeding season, usually only one brood but rarely two.
• August to October: migrates back to Africa.

Status and conservation

Willow Warblers prefer young, open, scrubby woodland

Woodland

Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

 with small trees, including human-altered habitats such as coppice and young plantation

Plantation

A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...

s up to 10–20 years old. High amounts of birch, alder and willow, with good lichen

Lichen

Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

 amounts, and water features (e.g. streams), fields with large amounts of bracken

Bracken

Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

 and mosses, and patches of low bramble

Bramble

Brambles are thorny plants of the genus Rubus, in the rose family . Bramble fruit is the fruit of any such plant, including the blackberry and raspberry. The word comes from Germanic *bram-bezi, whence also German Brombeere , Dutch Braam and French framboise...

 (for nest cover) are preferred, but it will use a wide range of other species, including young or open coniferous

Pinophyta

The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

 forests. Incorporating woodland ride edge thickets is beneficial, as is 15 metre woodland edges of varying structure and height. They prefer damp woodland areas. Thicket forming shrubs like blackthorn

Blackthorn

Prunus spinosa is a species of Prunus native to Europe, western Asia, and locally in northwest Africa. It is also locally naturalised in New Zealand and eastern North America....

 provide pockets of habitat. Deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 browsing can degrade the required low cover.

The highest population densities are found in Scandinavia (where it is the commonest bird of any), with up to 1,100 pairs per square kilometre, and a total population in Sweden and Finland of 24 million pairs. Lower densities occur further east, with peak densities of 27 pairs per square kilometre in central Siberia. Even lower densities are found on the southern edge of the breeding range, with just 9 pairs per square kilometre in Switzerland, and a total of just 100 pairs in the whole of northern Spain.

In England this species has on average decreased in population by 70% within the last 25 years, with the biggest declines in the southeast. In Scotland some increases have occurred. The Forestry Commission

Forestry Commission

The Forestry Commission is a non-ministerial government department responsible for forestry in Great Britain. Its mission is to protect and expand Britain's forests and woodlands and increase their value to society and the environment....

 offers grants under a scheme called England's Woodland Improvement Grant (EWIG); as does Natural England

Natural England

Natural England is the non-departmental public body of the UK government responsible for ensuring that England's natural environment, including its land, flora and fauna, freshwater and marine environments, geology and soils, are protected and improved...

s Environmental Stewardship

Environmental Stewardship

Environmental Stewardship is an agri-environment scheme run by the Department for Environment, Food and Rural Affairs in England. It was formally launched on 18 March 2005, although the first agreements did not start until 1 August 2005....

 Scheme.

History

The Willow Warbler was first scientifically described by Linnaeus

Carolus Linnaeus

Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 in his Systema Naturae

Systema Naturae

The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...

in 1758 under the genus Motacilla. and then transferred to the genus Phylloscopus (of which it is the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

) by Boie

Friedrich Boie

Friedrich Boie was a German scientist and brother of Heinrich Boie. He was born at Meldorf in Holstein and died at Kiel....

 in 1826.

Before the English name was standardised to Willow Warbler by William Yarrell

William Yarrell

William Yarrell was an English bookseller and naturalist.Yarrell is best known as the author of The History of British Fishes and The History of British Birds . The latter went into several editions and was the standard reference work for a generation of British ornithologists...

in 1843, it was sometimes called "willow wren".

External links

• Willow Warbler videos, photos & sounds on the Internet Bird Collection