About Acrocephalus gracilirostris (Hartlaub, 1864)
The lesser swamp warbler, scientifically named Acrocephalus gracilirostris (Hartlaub, 1864), is a plain-coloured, smallish bird. It measures 14–16 cm in length and weighs around 20 g. This species has rich brown upperparts and a distinct white supercilium. Its underparts are white, with a rufous wash covering the flanks. It has a long, strong bill with a slightly down-curved upper mandible; the bill is blackish-yellow and has a yellower base. The legs are blue-grey, and the eyes are brown. Adults of both sexes and juvenile birds are very similar in overall appearance. The song of the lesser swamp warbler is rich and melodious, consisting of a series of bubbly phrases that include trilling notes, such as cheerup chee trrreee. There are a large number of song variations, with pauses occurring between phrases.
