Marsh Warbler (Acrocephalus palustris)Distribution and seasonality in the UK
Status not yet classified · reporting peaks June · Reed Warblers and Allies · BOU category A
Contains OS data © Crown copyright and database right 2026 (grid squares, place names from OS Open Names). Northern Ireland place names: OSNI Open Data, OGL v3.0. County and country boundaries: Office for National Statistics, Open Government Licence v3.0. Coastline: Natural Earth. Bird records from the data partners listed here.
Marsh Warbler has been recorded in 33 of the 2,971 10 km squares covering UK land (1%) in records to 2026. Its strongest squares are in England and Scotland. Reporting peaks in June.
This species is protected under Schedule 1 of the Wildlife and Countryside Act 1981. It is an offence to disturb it at or near the nest without a licence. Breeding-season distribution is not shown and square-level counts are withheld.
- Very high
- 100% or more of visits
- High
- 17% to 100%
- Moderate
- 2% to 17%
- Low
- under 2%
- Surveyed, not recorded
- at least 20 qualifying visits, no record
- Insufficient records
- too few visits to say
- Not shown in the breeding season
- sensitive breeding species
- Lighter fill
- Few visits, lower confidence
- Small dot
- Occasional: a single record, or out of season
Seasonality
| Month | Relative to peak | Share of visits | Typical class |
|---|---|---|---|
| January | 0% | <1% | Insufficient records |
| February | 0% | <1% | Very high |
| March | 0% | <1% | Very high |
| April | 1% | <1% | Very high |
| May | 78% | <1% | Insufficient records |
| June | 100% | <1% | Insufficient records |
| July | 15% | <1% | Insufficient records |
| August | 13% | <1% | Insufficient records |
| September | 44% | <1% | Moderate |
| October | 30% | <1% | Low |
| November | 0% | <1% | Insufficient records |
| December | 0% | <1% | Insufficient records |