Overview
The willow warbler (Phylloscopus trochilus) is a very common and widespread leaf warbler which breeds throughout northern and temperate Europe and the Palearctic, from Ireland east to the Anadyr River basin in eastern Siberia. It is strongly migratory, with almost all of the population wintering in sub-Saharan Africa.
It is a bird of open woodlands with trees and ground cover for nesting, including most importantly birch, alder, and willow habitats. The nest is usually built in close contact with the ground, often in low vegetation. Like most Old World warblers (Sylviidae), this small passerine is insectivorous. In northern Europe, it is one of the first warblers to return in the spring, though later than the closely related chiffchaff.
Taxonomy
The willow warbler was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Motacilla trochilus. The willow warbler is now one of around 80 species placed in the genus Phylloscopus that was introduced by the German zoologist Friedrich Boie in 1826. The genus name combines the Ancient Greek meaning "leaf" and meaning "seeker" (from , "to watch"). The specific epithet is Ancient Greek meaning "wren".
Before the English name was standardised to willow warbler by William Yarrell in 1843, it was sometimes called "willow wren".
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