Size: 11–12.5 cm long and 7–15 g weight, with a 16-22 cm wingspan.

Vocalisations: 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.

Habitat: Willow warblers prefer young, open, scrubby woodland with small trees. High amounts of birch, alder and willow, with good lichen amounts, and water features (e.g., streams), fields with large amounts of bracken and mosses, and patches of low bramble (for nest cover) are preferred.

Behaviour: Willow warblers are migratory birds, breeding in Europe and migrating to southern Africa for the winter. They are unusual birds because they moult all their feathers twice a year - once at their breeding grounds and once at their wintering grounds; yet, the reason for this is unclear. Like other warblers, they are insectivorous, but will eat berries and fruit in autumn. Willow warblers are monogamous and form pairs, however, some males may pair up with more than one female. These birds breed from April to July. They build their nests in close contact with the ground, often in low vegetation. The female lays 4-8 eggs and incubates them alone. The chicks hatch naked and blind and for the first 10-11 days are fed by both parents.

Photo: pixabay.com