Common Reed Warbler
Acrocephalus scirpaceus
This is a medium-sized warbler, 13 cm (5.1 in) in length with a wing-span of 17–21 cm (6.7–8.3 in). The adult has an unstreaked brown back and buff underparts. The forehead is flattened, and the bill is strong and pointed. The sexes are identical, as with most warblers, but young birds are richer buff below. The common reed warbler looks similar to the great reed warbler, but the great reed warbler is larger in size and has a stronger supercilium. The song is a slow, chattering jit-jit-jit with typically acrocephaline whistles and mimicry added.
ID text from Wikipedia, CC BY-SA 4.0
Marsh Warbler
Acrocephalus palustris
This is a medium-sized warbler. It is very similar in appearance to several other acrocephaline warblers, such as the reed warbler which also occurs in wetlands and has a similar breeding range. The male's distinctive song is useful for identification, as no other member of the genus mimics other birds to any significant extent. The marsh warbler also tends to avoid the stands of pure reed which are the reed warbler's favoured habitat. The sexes are alike in appearance. Hybridisation with both reed warbler and Blyth's reed warbler has been occasionally recorded.
ID text from Wikipedia, CC BY-SA 4.0
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