About Acrocephalus gracilirostris (Hartlaub, 1864)
Scientific Classification and General Traits
The lesser swamp warbler, scientifically named Acrocephalus gracilirostris (Hartlaub, 1864), is a plain-coloured, smallish bird.
Size Measurements
It measures 14–16 cm in length and weighs around 20 g.
Upperpart and Head Markings
This species has rich brown upperparts and a distinct white supercilium.
Underpart Coloration
Its underparts are white, with a rufous wash covering the flanks.
Bill Characteristics
It has a long, strong bill with a slightly down-curved upper mandible; the bill is blackish-yellow and has a yellower base.
Leg and Eye Coloration
The legs are blue-grey, and the eyes are brown.
Plumage Similarity Across Age and Sex
Adults of both sexes and juvenile birds are very similar in overall appearance.
Core Song Structure
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.
Song Variation
There are a large number of song variations, with pauses occurring between phrases.
