General
Arctic Warbler: Medium-sized, active warbler with stout bill, olive-green back, olive-brown sides, and white throat and belly. Dark eye-lines contrast with pale yellow eyebrows curving upward behind eyes. Wings have faint pale bar on tips of greater coverts. Tail is square. Sexes are similar.
Range and Habitat
Arctic Warbler: Occurs in Fennoscandia and northern Asia, and is also established in North America, where they breed in Alaska. They migrate to Southeast Asia for the winter, having the longest migration route of any Old World insectivorous bird. Preferred habitats include birch woods, willow thickets, mixed coniferous-deciduous open forests, and grassy tundra. Rare vagrant to the UK.
Breeding and Nesting
Arctic Warbler: Five to seven white eggs, sometimes spotted with red-brown, are laid in a sphere-shaped nest built by the female on the ground, hidden in thickets of willow and birch. Female incubates eggs for about 13 days.
Foraging and Feeding
Arctic Warbler: Diet includes insects and other small invertebrates.
Vocalisation
Arctic Warbler: Song is a long, loud series of toneless, buzzing notes. Call is a buzzing "dzik."
Similar Species
Arctic Warbler: Chiffchaff has a light brown eyebrow. Willow Warbler has a dark eye line. Garden Warbler has no eyebrow. All three are very common.