Willow Warbler

• GeneralIt weighs 9 grams and crosses the Sahara twice a year.
• The populations that breed in the far east of Siberia travel more than twelve thousand kilometres to southern Africa twice a year, the longest migration of any bird weighing less than ten grams.
• It moults twice a year, which is exceptional among the leaf warblers: it renews its entire plumage on the breeding grounds and again on the wintering grounds, an enormous energy cost for such a small bird.
• Its song, a descending cascade of pure, wistful notes, is easily told from the monotonous chiff-chaff of the common chiffchaff, with which it shares its habitat across half of Europe.

Skeleton type

Vertebrate - internal bony skeleton (bird)

Habitat and environment

Open birch and willow woodland, copses and scrub of Eurasia; winters in sub-Saharan Africa

Sexual maturity

12 months

Gestation / incubation

13 days of incubation

Litter / clutch size

6 eggs

Sources consulted: Wikipedia (en): Willow warbler