Cetti’s warbler is a small, stocky warbler with short, round wings, a long tail, a domed head, and fine bill. It is the only bush warbler to be found outside Asia and is famous for its loud, explosive bursts of song. It was first recorded in the UK in the 1960s and first bred in 1973. It is also the only British bird to have just ten tail feathers rather than the usual twelve.
Breeding birds: 2,000 pairs
Family: Bush warblers
Cetti’s warblers have warm brown upperparts with darker brown flight feathers and tail. The rectrices have reddish-brown outer edges. The underparts are pale grey or white with a brown tinge to the sides of the breast, and a reddish-brown wash on the flanks. The undertail coverts have white tips.
On the head, the forehead, crown, and nape are rufous-brown, and there is a narrow white or pale grey supercilium. The lores and eyes tripe are dark brown and they have a thin white eye-ring. The cheeks and ear coverts are dull grey-brown. The short, pointed bill is dark brown or black with a pink base on the lower mandible, the eyes are dark brown, and the legs and feet are pink or brown.
Males and females are similar but the male is larger.
Juvenile Cetti’s warblers are duller than the adults.
Cetti’s warblers breed from April to August and produce 2 broods a season. The build their nest in low, tangled vegetation in shrubs or marshes. The nest is a large, untidy, cup-shaped structure made from leaves, dry grass, and plant fibres, and lined with feathers, hair, and flowers.
Cetti’s warblers lay 4-5 brick-red eggs which are incubated by the female alone for 16-17 days. Chicks are fed insects mainly by the female until they fledge at 14-15 days after hatching, while the male defends the nest site.. They are fed for a further 2 weeks by both parents.
Cetti’s warblers eat mostly insects and aquatic invertebrates. They will also eat snails, worms, and occasionally seeds. It forages mostly on the ground but will also take prey from the surface of water or chase it in flight.
Cetti’s warblers live in damp areas close to wetlands. They can be seen all year round particularly in southern England and South Wales.
Cetti’s warblers are named after the 18th century zoologist, mathematician and Jesuit priest, Francesco Cetti.