The Willow Warbler
) is a very common and widespread leaf warbler
which breeds throughout northern and temperate Europe and Asia, 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
, and willow
habitats. The nest is usually built in close contact with the ground, often in low vegetation. Like most Old World warblers, this small passerine
In northern Europe, it is one of the first warblers
to return in the spring though is later than the closely related Chiffchaff Phylloscopus collybita
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.