Technical summary · Updated 28 October 2026
Two different purposes
A breeding-bird survey builds a picture of how birds use a site through the breeding period. A pre-work check asks a narrower question about nesting activity in the area about to be affected. A check immediately before works does not replace a seasonal survey where the planning assessment needs that wider evidence.
Dates are not a clearance instruction
March to August is a broad planning guide for breeding-bird surveys, with timing adjusted to the species. Birds can nest outside a simplified calendar window. Natural England’s standing advice explains the protection of nests in use or being built, so a date alone cannot establish that vegetation clearance is acceptable.
A practical programme
Consider likely nesting habitat and the proposed sequence of works early. Where checks are required, agree their scope and timing with the ecologist and provide a clear process if a nest is found. The aim is to avoid disturbance and programme work around the actual evidence, rather than treating a coloured calendar cell as permission to start.
Sources & further reading
This is an explanatory summary of the cited evidence, not an original research paper or a site-specific survey specification.