Quick facts

Common name: willow warbler

Scientific name: Phylloscopus trochilus

Family: Sylviidae (warblers)

Habitat: woodland, scrub, gardens

Diet: invertebrates

Predators: birds of prey, domestic cats

Origin: native

What do willow warblers look like?

Willow warblers have a yellowish or olive green breast with paler underparts. They have a brownish head with a pale yellow-green stripe above the eye, and flesh-coloured legs. 

Long primary feathers on its brown wings give this bird a long-winged appearance, reflecting the huge distances it travels on migration. With a typical weight of around 9g, this is a dainty bird of a similar size to a blue tit. 

Not to be confused with: the chiffchaff, which looks very similar but can be differentiated by its song and darker legs. Chiffchaffs make a ‘chiff-chaff’ sound while willow warblers have a lovely warble that descends in scale.

Willow warbler on branch eating snail

Credit: Tony Cox / WTML

What do willow warblers eat?

Willow warblers are active during the day, feeding on a variety of small insects and spiders, as well as fruits and berries in the autumn.

How do willow warblers breed?

Willow warblers build distinctive, dome-shaped nests with a hole in the side, close to the ground. Very small eggs are laid in these oven-like nests – they are so tiny that three eggs weigh the same as a penny.

The smooth, glossy white eggs are speckled with reddish-brown. The female incubates the eggs by herself, but after the young hatch they are fed by both parents.

Juvenile willow warbler on branch

Credit: John Bridges / WTML

Do willow warblers migrate?

Willow warblers leave the UK between July and September to spend the winter in Africa, south of the Sahara.

Did you know?

Unlike most other birds, willow warblers moult their feathers twice a year.

Where do willow warblers live?

Willow warblers like young, open woodland. They are easy to spot (or hear) among birch, willow and alder, all of which are usually found near water.

Willow warbler adult and chicks in nest

Credit: Robert Thompson / naturepl.com

Signs and spotting tips

Look out for willow warblers in woodland and scrub from March onwards. Their melancholy song descends in scale and is unmistakeable.

Willow warbler song

Audio: Tony Fulford / xeno-canto.org

Threats and conservation

The number of willow warblers in the UK has fallen by around 44% since 1970. Populations are, however, faring better in Scotland and the north of England than in the south, possibly due to changes in the availability of favourable breeding habitat.