General
Willow Warbler: Small leaf warbler with green-brown upperparts and buff to yellow-white underparts that become less yellow as the summer progresses. The head has a brown eyestripe and a pale yellow eyebrow. The bill is brown and the legs and feet range in colour from dark brown to flesh-coloured. Sexes are similar. Juvenile has more yellow on the underparts.
Range and Habitat
Willow Warbler: Widespread in the UK and Ireland. Most arrive in April and begin to leave in August. Found in open woodlands, birch woods, plantations, abandoned industrial land and moorland edges. Breeds from northern Europe to Russia and Asia. Spends the winter in southern and central Africa.
Breeding and Nesting
Willow Warbler: Four to eight white eggs with red-brown speckles are laid in a domed nest on the ground hidden among vegetation. Female builds the nest from lichens, leaves and moss. Eggs are incubated for 10 to 17 days by the female. Chicks are fed by both parents and fledge 13 to 16 days later.
Foraging and Feeding
Willow Warbler: Feeds primarily on invertebrates such as aphids, spiders, caterpillars, flies, midges and beetles. Feeds on berries towards the end of summer and into the fall.
Vocalisation
Willow Warbler: Long melodious series, begins soft, rises in volume, and finally falls away. Call is a relatively simple "hoo-eet."
Similar Species
Willow Warbler: Chiffchaff is marginally smaller and tends to be elongated and sleeker. It is also likely to have darker legs. The Wood Warbler has longer wings, yellow in the underparts, and a more distinct eyebrow. Call is the best way to tell them apart.