A Eurasian warbler, Acrocephalus palustris (family Sylviidae), which frequents reed beds, winters in Africa, and has a tendency to mimic other birds in its song.
Origin
Mid 19th century; earliest use found in John Gould (1804–1881), ornithologist and publisher.
Definition of marsh warbler in US English:
marsh warbler
noun
A Eurasian warbler, Acrocephalus palustris (family Sylviidae), which frequents reed beds, winters in Africa, and has a tendency to mimic other birds in its song.
Origin
Mid 19th century; earliest use found in John Gould (1804–1881), ornithologist and publisher.