Grasshopper Warbler (Locustella naevia)Where and when to see it in the UK
Status not yet classified · reporting peaks April to May · Grasshopper Warblers, Grassbirds, and Allies · BOU category A
Peak months
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.
Grasshopper Warbler has been recorded in 1,382 of the 2,971 10 km squares covering UK land (47%) in records to 2026. Its strongest squares are in England, Scotland and Wales. Reporting peaks in April to May.
Conservation status: Least Concern (IUCN Red List, LC)
View on the IUCN Red List- Very high
- 39% or more of visits
- High
- 5% to 39%
- Moderate
- 2% to 5%
- Low
- under 2%
- Surveyed, not recorded
- at least 20 qualifying visits, no record
- Insufficient records
- too few visits to say
- Lighter fill
- Few visits, lower confidence
- Small dot
- Occasional: a single record, or out of season
Relative to this species' best squares (how classes are calculated)
Seasonality
| Month | Relative to peak | Share of visits | Typical class |
|---|---|---|---|
| January | 0% | <1% | Very high |
| February | 0% | <1% | Very high |
| March | 0% | <1% | Very high |
| April | 100% | 2% | Very high |
| May | 93% | 2% | High |
| June | 54% | 1% | Very high |
| July | 50% | 1% | Very high |
| August | 18% | <1% | Low |
| September | 8% | <1% | Low |
| October | 1% | <1% | Low |
| November | 0% | <1% | Very high |
| December | 0% | <1% | Very high |
Squares with the highest reporting rate in April
| Square | Where | Share of visits | Class |
|---|---|---|---|
| C73 | Causeway Coast and Glens, Northern Ireland | 100% | Very high |
| C84 | Causeway Coast and Glens, Northern Ireland | 100% | Very high |
| C94 | Causeway Coast and Glens, Northern Ireland | 100% | Very high |
| D14 | Causeway Coast and Glens, Northern Ireland | 100% | Very high |
| D20 | Mid and East Antrim, Northern Ireland | 100% | Very high |
| H32 | Fermanagh and Omagh, Northern Ireland | 100% | Very high |
| H86 | Mid Ulster, Northern Ireland | 100% | Very high |
| J19 | Antrim and Newtownabbey, Northern Ireland | 100% | Very high |
| J35 | Newry, Mourne and Down, Northern Ireland | 100% | Very high |
| J39 | Mid and East Antrim, Northern Ireland | 100% | Very high |