Booted Warbler (Iduna caligata)Where and when to see it in the UK
Status not yet classified · reporting peaks August · Reed Warblers 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.
Booted Warbler has been recorded in 31 of the 2,971 10 km squares covering UK land (1%) in records to 2026. Its strongest squares are in England, Scotland and Wales. Reporting peaks in August.
Conservation status: Least Concern (IUCN Red List, LC)
View on the IUCN Red List- Very high
- 100% or more of visits
- High
- <1% to 100%
- Moderate
- <1% to <1%
- Low
- under <1%
- 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% | Insufficient records |
| February | 0% | <1% | Insufficient records |
| March | 0% | <1% | Insufficient records |
| April | 0% | <1% | Insufficient records |
| May | 0% | <1% | Insufficient records |
| June | 2% | <1% | High |
| July | 0% | <1% | Insufficient records |
| August | 100% | <1% | High |
| September | 32% | <1% | Very high |
| October | 64% | <1% | Low |
| November | 0% | <1% | Insufficient records |
| December | 0% | <1% | Insufficient records |
Squares with the highest reporting rate in August
| Square | Where | Share of visits | Class |
|---|---|---|---|
| HP61 | Shetland Islands, Scotland | 100% | Very high |
| HU40 | Shetland Islands, Scotland | 100% | Very high |
| NT69 | Sea, off Fife | 100% | Very high |
| NU20 | Northumberland, England | 100% | Very high |
| HU67 | Sea, off Shetland Islands | 16% | High |
| TM23 | Suffolk, England | 6% | High |
| HZ27 | Shetland Islands, Scotland | 4% | High |
| HY75 | Sea, off Orkney Islands | 3% | High |
| NZ46 | South Tyneside, England | 1% | High |
| SV91 | Isles of Scilly, England | <1% | Moderate |