Ecological survey calendar › Birds
When to survey for birds in Wales and England
Updated November 2026. Based on the Bird Survey Guidelines (2022) for assessing ecological impacts.
Breeding bird surveys run from late March to early July, normally as six visits starting around dawn. Wintering bird surveys run monthly from November to February, adding October and March where passage birds matter. Vegetation is best cleared between September and February, after a nest check.
Survey windows, sensitive periods and works timing
| Activity | Type | When | Notes |
|---|---|---|---|
| Breeding bird surveys | Survey | mid-Mar to mid-Jul; mid-Jul to Aug (not ideal) | Six visits spread evenly from late March to early July, starting around dawn, with at least one evening visit. Later visits suit some species. |
| Wintering bird surveys | Survey | Oct (not ideal); Nov to Feb; Mar (not ideal) | At least monthly visits November to February, adding October and March where passage birds matter. Time coastal visits to the tides. |
| Nesting season | Sensitive period | Mar to Aug | Some species nest outside these months, so a nest check is needed before clearance at any time of year. |
| Vegetation clearance | Works window | Sep to Feb | Outside the main nesting season, with a nest check within 48 hours before works. |
Optimal survey Possible, not ideal Sensitive period Works window
Timing depends on the site, the weather in a given year and what the planning authority and licensing body need. Upland and northern sites can run later. See every species group side by side on the ecological survey calendar.
About birds
Most nesting happens in spring and early summer, but some species start in February and others carry on into September. A nest check by an ecologist is the safeguard whenever vegetation or structures are cleared.
Legal protection
All wild birds, their active nests and eggs are protected under section 1 of the Wildlife and Countryside Act 1981. Schedule 1 species are also protected from disturbance while nesting.
Licensing
Wales: No licence is available to remove active nests for development. Survey work near Schedule 1 nests needs a licence from Natural Resources Wales.
England: No licence is available to remove active nests for development. Survey work near Schedule 1 nests needs a licence from Natural England.
Practical tips
- Clear vegetation between September and February wherever you can.
- Ecoleg's standard is a nest check no more than 48 hours before clearance. An active nest stops work nearby until the young have fledged.
Common questions
When is breeding bird survey season?
Late March to early July, normally six visits spread evenly through that period, starting around dawn, with at least one evening visit (Bird Survey Guidelines, 2022).
Is there a legal bird nesting season?
The law protects any active nest whenever it occurs, so there is no fixed legal season. March to August is the main season used in practice, and Ecoleg uses March to August inclusive as its standard.
Can I clear vegetation in spring or summer?
Only after an ecologist has checked for active nests, no more than 48 hours before work starts. An active nest stops work nearby until the young have fledged. Clearing between September and February avoids most of the risk.
When are wintering bird surveys done?
At least monthly from November to February, with October and March added where passage birds matter. Coastal visits are timed to the tides.
Need a survey or advice on timing? Ecoleg's licensed ecologists programme surveys across Wales and England so the right work happens in the right season. Call 07356 123706.
Request a quoteSee the full calendarSources
- Bird Survey & Assessment Steering Group (2022) Bird Survey Guidelines for assessing ecological impacts.
- Ecoleg house standard (2026): nesting season March to August inclusive; nest check within 48 hours before works.
Updated November 2026. General guidance only: confirm timing for your site with a suitably qualified ecologist.