© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, M. & W. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland). Recording: Jan-Erik Bruun. All rights reserved.
- Family: Reed warblers – Acrocephalidae
- Appearance: Common in reed beds. Upper parts olive brown with streaked patterning, except for unmarked reddish brown rump. Wide whitish eyebrow stripe distinctive.
- Size: Length 11.5–13 cm, weight 11–15 g.
- Nest: On the ground or low in vegetation, attached to plant stems. Made of sedge and reed leaves and aquatic moss, lined with hair and the soft heads of reeds.
- Breeding: 3–7 eggs laid in May–June, incubated mainly by female for 12–15 days. Fledglings leave nest within 10–16 days.
- Occurrence: Breeds in moist scrubland and reed beds throughout Finland. Breeding population estimated at 200,000–400,000 pairs.
- Migration: Nocturnal. Leaves Finland August–September, returning May–June after wintering in tropical Africa.
- Diet: Invertebrates.
- Calls: A clicking “chek” call. Song performed rapidly in reed beds sounds hectic and hurried.
- Endangerment: Near threatened, protected.
Sedge Warblers can be distinguished from other warblers that breed in Finland by their reddish brown rumps, their broad off-white eyebrow stripes and the dark streaking on their backs. Adults’ underparts are off-white, with no streaking on their breasts. Juveniles in their first autumn have faintly speckled yellowish brown underparts. Sedge Warblers also have a fairly visible dark streak along their caps. Their legs are pale brownish grey, their beaks are black with a yellowish red base to the lower mandible, and their irises are brown.