Marsh Warbler (Acrocephalus palustris)

OTHER NAMES: N/A
Latin Etymology: Acrocephalus ("topmost head") palustris ("loving marshes") 

Adult Marsh Warbler (Acrocephalus palustris) at Branston Gravel Pits, Staffordshire - May 2024

Featured Subspecies: N/A
Weight: 11-15g  /  Length: 13-15cm  /  Wingspan: 18-21cm
UK RED LIST / IUCN Red List: Least Concern

Like the Savi's Warbler, the Marsh Warbler is a small, brown, reedbed species for which the UK is the very last fringe of it's range, with only a tiny precarious handful of pairs still breeding in the country. Superficially similar to reed warblers, they differ subtly in plumage, but more conspicuusly in song where they incorporate a spectacular range of mimicry, with an average of 75 species by each individual! This also frequently includes the songs of African species from their Summer range, bringing songs to a European soundscape seen a continent away!

Related Species:
Order: Passeriformes
Family: Acrocephalidae
Genus: Acrocephalus
SUBSPECIES: none - monotypic 

 - Sighting Locations -

UNITED KINGDOM - A passage migrant and fringe breeding species (1-3 pairs)
 - Vagrant seen at Branston Gravel Pits in May 2024 .

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Great Reed Warbler (Acrocephalus arundinaceus)

OTHER NAMES: N/A
Latin Etymology: Acrocephalus ("topmost head") arundinaceus ("like a reed") 

Adult male Great Reed Warbler (Acrocephalus arundinaceus) at RSPB Ouse Fen, Cambridgeshure - May 2024

Featured Subspecies: Acrocephalus arundinaceus arundinaceus
Weight: 22-38g/  /  Length: 16-21cm  /  Wingspan: 25-30cm
NO UK STATUS / IUCN Red List: Least Concern

A huge warbler distinct on its size alone, more resembling a thrush in size and also the vibe of it's song. A species of reedbeds of Europe and Central Asia, migrating in Winter to Sub-Saharan Africa.  Closely related to the Oriental and Basra Reed Warblers, of which the former was formerly considered a subspecies, though it is a slightly larger bird than either of those species. Normally not found in Britain, this individual was singing at Ouse Fen in May 2024. 

Related Species:
Order: Passeriformes
Family: Acrocephalidae
Genus: Acrocephalus
SUBSPECIES: A. a. arundinaceus, A. a. zarudnyi

 - Sighting Locations -

UNITED KINGDOM - A regular vagrant
 - A vagrant seen at RSPB Ouse Fen in May 2024 .

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Oriental Reed Warbler (Acrocephalus orientalis)

OTHER NAMES: N/A
Latin Etymology: Acrocephalus ("topmost head") orientalis ("of the orient")

Adult Oriental Reed Warbler (Acrocephalus orientalis) at Florican Grasslands, Cambodia - February 2019

Featured Subspecies: N/A
Weight: 18-47g  /  Length: 18-20cm  /  Wingspan: 23-26cm
NO UK STATUS / IUCN Red List: Least Concern

While the name I'd heard in advance made me imagine another small reed-type warbler, this is actually a recent split from the Great Reed Warbler - a giant amongst warblers more on the scale of a redwing - far far bigger than any resident warbler of the UK.  It is highly migratory, breeding in Mongolia, North-East China, Korea, Japan and Siberia, and wintering in South-East Asia where I saw it. 

Related Species:
Order: Passeriformes
Family: Acrocephalidae
Genus: Acrocephalus
SUBSPECIES: none - monotypic 

 - Sighting Locations -

CAMBODIA - Khmer name: ចាបដូនតា ("grandfather")

A non-breeding migrant.

SINGAPORE / CAMBODIA 2019 TRIP - One seen at Florican Grassland Reserve

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Sedge Warbler (Acrocephalus schoenobaenus)

OTHER NAMES: European Sedge Warbler
Latin Etymology: Acrocephalus ("topmost head") schoenobaenus ("reed tread")

Adult Sedge Warbler (Acrocephalus schoenobaenus) at Frampton Marshes, Lincolnshire, May 2026 

Featured Subspecies: N/A
Weight: 10-13g  /  Length: 13cm  /  Wingspan: 19cm
UK GREEN LIST / IUCN Red List: Least Concern

Sedge Warblers are one of the commoner warblers in the UK, albeit limited mainly to reed-bed. Possibly slightly easier to see than the other major reed specialist (the reed warbler) it does share the disadvantage of all reed-bed species that it very much depends on how obliging the individual is on how easy they are to get a look at - they can vary wildly between skulking and singing from prominent positions.  This is a Summer migrant, and so only present for half the year, but can be differentiated from the Reed Warbler by the prominent pale eye-stripe and more mottled plumage.  Despite the name, it's not in any way confined to sedges, and can be found in much the same habitat as the Reed Warbler.

Related Species:

Order: Passeriformes

Family: Acrocephalidae
Genus: Acrocephalus
Subspecies: none - monotypic

- Sighting Locations -

UNITED KINGDOM - A common Summer breeding migrant to reed-beds (290,000 territories)

 - Birds seen at Rutland Water, Rainham Marshes, Blakenham and other wetland sites

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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