Partial song in winter quarters

The Blyth's Reed Warbler, Acrocephalus dumetorum, is an Old World warbler in the genus Acrocephalus. It breeds in temperate Asia and easternmost Europe. It is migratory, wintering in India and Sri Lanka. It is one of the most common winter warblers in those countries. It is a rare vagrant to western Europe.

This small passerine bird is a species found in scrub or clearings, often near water, but it is not found in marshes. 4-6 eggs are laid in a nest in a bush.

At New Alipore in Kolkata, West Bengal, India.

This is a medium-sized warbler, 12.5-14 cm in length. The adult has a plain brown back and pale underparts. It can easily be confused with Reed Warbler, Marsh Warbler and some of the Hippolais warblers. It is most like Reed Warbler but is greyer on the back, the forehead is less flattened and the bill is less strong and pointed. The sexes are identical, as with most warblers, but young birds are yellower below.

The habitat is different from the reed beds favoured by Reed Warbler or the rank vegetation of Marsh Warbler, this species choosing trees or bushes as songposts. Like most warblers, Marsh Warbler is insectivorous, but will take other small food items including berries.

In the breeding season, the best identification feature is the song, which is slow and repetitive, with much mimicry of other birds, punctuated with scales and typically acrocephaline whistles.

This bird is named after the British zoologist Edward Blyth.