The Yellow-browed Warbler (Phylloscopus inornatus) is one of Sweden's most sought-after autumn rarities, a species that breeds in the Siberian taiga yet sends small numbers to the Swedish coast every year, above all to Ottenby and Falsterbo. It is a tiny leaf warbler, only about 9-11 cm long, one of the smallest birds in Europe, barely bigger than a Goldcrest. The upperparts are olive-green and the underside yellowish-white, but the best marks are two clear yellowish-white wing bars and a bold, pale-yellow eyebrow stripe reaching well back across the head; a dark eye-stripe and a pale panel on the inner secondaries add to the contrast. The bird is constantly active, hopping between twigs and often hanging upside down like a tit.
Most Yellow-browed Warblers are first detected by call: a penetrating, upward-inflected, slightly wheezy "tsu-est" or "tsoo-eet", fairly easy to learn and able to reveal the bird even when hidden in dense scrub, since it often turns up alone and quiet and the call can be the only clue to its presence. It breeds across the Siberian taiga from northern Russia east to the Pacific and normally winters in southeast Asia, building a domed, oven-shaped nest on or near the ground, well hidden under tussocks or low vegetation. It does not breed in Sweden; the birds seen here in autumn, mostly September and October at scrub-rich coastal sites such as Ottenby, Falsterbo, Nidingen, Hoburgen and Landsort, are thought to be young birds performing so-called reverse migration, flying northwest into Europe instead of southeast toward their wintering grounds. Numbers vary between autumns, from a handful of individuals to tens of birds, making it a fairly regular Siberian vagrant rather than a pure rarity. The diet is small insects, larvae, aphids and spiders gleaned from leaves and branches, foraged high in deciduous trees and bushes. The best chance is a calm, clear day in late September or October at a coastal site.
Read about this species in Swedish →