Marsh Warbler

Acrocephalus palustris (Bechstein, 1798) MW MARWA 12500
Family: Passeriformes > Acrocephalidae

Marsh Warbler, Graham Clarke

Resembling a Reed Warbler in appearance and behaviour, this scare summer visitor and breeder is most easily identified by its complex song.

Marsh Warblers are rarely found in Britain and are absent from the island of Ireland. A small number of individuals occur on passage each year, mostly on the eastern coasts of England and Scotland, and in England, a dwindling number stays to breed. There has been an eastward shift in the distribution of the remaining breeding pairs in recent years. The Marsh Warbler has been on the UK Red List since 1996.

Marsh Warblers favour scrubby, grassland and reedbed habitats. The species largely breeds in central, northern and eastern Europe, and winters in south-east Africa. Males frequently incorporate songs from other species, including those encountered on their wintering grounds, when singing during the breeding season.

Select a topic for more facts and statistics about the Marsh Warbler

  • Breeding
  • Winter


Marsh Warbler identification is often difficult.


Listen to example recordings of the main vocalisations of Marsh Warbler, provided by xeno-canto contributors.


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Status and Trends

Population size and trends and patterns of distribution based on BTO surveys and atlases with data collected by BTO volunteers.


This species can be found on the following statutory and conservation listings and schedules.



The breeding population at the start ofthe twentieth century may have been over 180 pairs, with numbers beginning to decline after 1950 (Kelsey et al. 1989). During the 1970s there were around 60–80 pairs of Marsh Warbler breeding in the UK, with the stronghold in Worcestershire (Kelsey et al. 1989). Declines occurred during the 1980s and 1990s and breeding in Worcestershire was last confirmed in 1995, with small numbers subsequently continuing to breed elsewhere in the UK, mostly at east coast locations (Bell et al. 2021). The five-year mean figure reported to the Rare Breeding Birds Panel for the period 2015–2019 was just 10 breeding pairs (Eaton et al. 2021).


Singing Marsh Warblers apperar rather unpredictably and few sites are occupied in successive seasons. The breeding-season distribution map shows a strong bias towards the east coast of Britain, reflecting this species’ easterly direction of arrival from its East African wintering grounds.

Occupied 10-km squares in UK

European Distribution Map

European Breeding Bird Atlas 2


Up until the late 1980s, Marsh Warbler distribution was very different, with a regular population in southwest England between Worcestershire and Somerset. From a high of 180 pairs the population dwindled to extinction over 80 years. Subsequently, a small population appeared in Kent but that too disappeared, with disturbance and egg-collecting thought to have contributed to their demise.


Marsh Warbler is a rare summer visitor, arriving in mid May. Additionally small numbers are encountered on autumn migration in September.

Weekly occurence of Marsh Warbler from BirdTrack
Weekly occurrence patterns (shaded cells) and reporting rates (vertical bars) based on BirdTrack data. Reporting rates give the likelihood of encountering the species each week.


Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.

An overview of year-round movements for the whole of Europe can be seen on the EuroBirdPortal viewer.


View a summary of recoveries in the Online Ringing Report.

Foreign locations of birds ringed or recovered in Britain & Ireland

Foreign locations of Marsh Warbler ringed or recovered in Britain & Ireland
Encountered in: Winter (Nov-Feb); Spring (Mar-Apr); Summer (May-Jul); Autumn (Aug-Oct)


Lifecycle and body size information about Marsh Warbler, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.



View number ringed each year in the Online Ringing Report


Feather measurements and photos on featherbase


For information in another language (where available) click on a linked name

Gaelic: Ceileiriche-fèithe
Welsh: Telor Gwerni
Catalan: boscarla menjamosquits
Czech: rákosník zpevný
Danish: Kærsanger
Dutch: Bosrietzanger
Estonian: soo-roolind e. putke-roolind
Finnish: luhtakerttunen
French: Rousserolle verderolle
German: Sumpfrohrsänger
Hungarian: énekes nádiposzáta
Icelandic: Seljusöngvari
Irish: Ceolaire Corraigh
Italian: Cannaiola verdognola
Latvian: purva kaukis
Lithuanian: karkline nendrinuke
Norwegian: Myrsanger
Polish: lozówka
Portuguese: felosa-palustre
Slovak: trsteniarik obycajný
Slovenian: mocvirska trstnica
Spanish: Carricero políglota
Swedish: kärrsångare


Interpretation and scientific publications about Marsh Warbler from BTO scientists.


Causes of change

Habitat changes including fragmentation and natural succession may have made some sites less suitable in the Worcestershire stronghold, but as some suitable habitat remained it is likely that other factors also contributed which may have included disturbance from birdwatchers and egg collectors; additionally the isolation of the population meant that immigration would have been limited and the population would have been more at risk from chance events affecting a large proportion of birds during winter or on migration (Kelsey et al. 1989; Bell et al. 2021). The UK remains at the edge of the species' breeding range and therefore the small remaining population remains vulnerable even though suitable habitat exists.

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