Savi's Warbler (Locustella luscinioides) is one of Sweden's most elusive songbirds, living hidden deep within dense reedbeds and betraying its presence almost solely through its mechanical, buzzing song. At 13–15 cm long — about the size of a Reed Warbler — it has a uniformly warm rust-brown upperside without streaking, a light grey to whitish underside with an indistinct brownish tinge on the sides and breast, and a crown slightly darker than the back. It has a narrow, pointed bill and lacks the pale eyebrow stripe of the Reed Warbler, an important field mark, while its round, graduated tail is often held slightly raised. In the field it is extremely hard to see, slipping through reed corridors with a mouse-like agility and rarely showing itself in the open.
Its song leaves no doubt as to its identity: an unbroken, insect-like buzz, "zrrrrrr", continuing for minutes without pause, even in pitch, similar to the River Warbler's but lower and softer — closer to the hum of an electric motor at low speed. Males sing readily at night and during morning and evening, hidden among the reed stems. Savi's Warbler has belonged to the Swedish breeding avifauna since the 1990s and now breeds sparsely in southern and central Sweden, mainly around lakes and wetlands in Skåne, Blekinge, Öland and the Mälaren valley, with a small national population of only a couple of hundred pairs; it is classed as Least Concern. The species is tied to dense, tall stands of reed at lakes, ponds and river mouths, requiring a mosaic of reed mixed with open water and bushes, and avoids narrow reed strips. Food consists of insects and spiders picked from reed leaves and the water surface, and the nest is built low in the reeds, holding 4–5 eggs incubated for around 13–14 days. As a long-distance migrant, it winters in East Africa, including Ethiopia, Sudan and Kenya.
Read about this species in Swedish →