The marsh grassbird, also known as the Japanese swamp warbler, is a species of Old World warbler in the family Locustellidae. It is found in China, Japan, South Korea, Mongolia, and Russia.
Region
East Asia
Typical Environment
Breeds in lowland marshes with extensive reed and sedge cover in Japan and parts of northeastern China and the Russian Far East. It also occurs in the Korean Peninsula and has been recorded as a migrant or rare breeder in surrounding regions, including Mongolia. Outside the breeding season some birds disperse to warmer lowlands, including rice-field landscapes and coastal wetlands. Habitat loss through wetland drainage and river modification has caused range fragmentation.
Altitude Range
0–1000 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
Also called the Japanese swamp warbler, the marsh grassbird is a secretive reedbed specialist in the family Locustellidae. It skulkily moves through tall sedges and reeds and is easiest to detect by its insect-like, reeling song. The species is threatened by drainage and conversion of wetlands and rice paddies, leading to fragmented populations. Conservation efforts focus on protecting lowland marshes and maintaining water levels suitable for breeding.
Temperament
secretive and territorial
Flight Pattern
short rapid wingbeats with low, fluttering flights over reeds; occasional brief song-flights
Social Behavior
Generally solitary during the breeding season, with males establishing territories in dense reedbeds. Nests are cup-shaped and placed low among reeds or sedges. Pairs are unobtrusive and rely on cover for protection, with both adults feeding the nestlings.
Migratory Pattern
Partial migrant
Song Description
Song is a sustained, insect-like reel with buzzy, mechanical trills delivered from concealed perches or during short song-flights. Calls include sharp ticks and dry chatters, especially when alarmed.
