Willow warbler

Phylloscopus trochilus

Photo by Arend Wassink (Birds of Kazakhstan)

Common name:
willow warbler (en); felosa-musical (pt); pouillot fitis (fr); mosquitero musical (es); fitis (de)

Taxonomy:
Order Passeriformes
Family Sylviidae

Range:
This species throughout most of Europe and northern Asia, from the northern Iberian Peninsula and the British Isles to northern Scandinavia and east through Poland and the Ukraine into most of Russia as far as the pacific coast and south to northern Kazakhstan and marginally into Mongolia. they migrate south and south-west to winter throughout sub-Saharan Africa.

Size:
These birds are 11-12,5 cm long and have a wingspan of 17-22 cm. They weigh 6-15 g.

Habitat:
The willow warbler is found breeding in a wide range of habitats, including deciduous and mixed forests in both temperate and boreal areas, forest clearings, open scrubby woodlands, scrublands, plantations, orchards and gardens. Outside the breeding season they also use mangroves, tropical forests, dry grasslands and savannas, swamps and lakes. They are present from sea level up to an altitude of 1.000 m.

Diet:
They feed mainly on small insects and spiders, as well as their eggs and larvae. Outside the breeding season fruits, berries and other plant materials are also an important part of their diet.

Breeding:
Willow warblers breed in April-August. The nest is built mostly by the female, consisting of a domed structure made of dry grass, leaves, stems, moss, lichen, twigs and bark woven together, and lined with animal hair and feathers. It is usually placed on the ground, well concealed among grass or at the base of a scrub or tree. Occasionally, the willow warbler may place the nest in a tree, crevice or creeper, up to 5 m above the ground. The female lays 4-8 glossy white eggs with reddish-brown speckles, which she mainly incubates alone for 10-16 days. The chicks are fed mostly by the female and fledge 11-15 days after hatching, becoming fully independent 2 weeks later.

Conservation:
IUCN status - LC (Least Concern)
This species has an extremely large breeding range and a global population roughly estimated at 340-1.200 million individuals. In Europe, populations have undergone a moderate decline over the last 3 decades.