Cetti's Warbler

• GeneralIt is heard far more than seen: it sings in explosive bursts from deep cover.
• Its eggs are an intense brick red, a colour that is very unusual among European birds.
• The nest is built by the male, but the female incubates and raises the chicks practically alone.
• Prolonged cold spells can wipe out whole populations: that is what happened in the Basque Country after the one in January 1985.

Skeleton type

Vertebrate - internal bony skeleton (bird)

Habitat and environment

Reedbeds, damp bramble thickets and river banks

Birth weight

The eggs weigh about 1.8 g

Gestation / incubation

16 days, by the female alone. The chicks fledge at 14-16 days and are independent at 30

Litter / clutch size

2-5 eggs of a distinctive brick-red colour, with up to two clutches a year between March and July

Sources consulted: SEO/BirdLife (ficha y III Atlas de las aves en época de reproducción en España) · IUCN Red List · Asturnatura · Moreno-Opo 2022, III Atlas · MITECO · Villarán 2000, Butlletí del Grup Català d'Anellament 17 · Araújo et al. 2016

Best time: All year round; it is resident and sings even in winter