Nesting birds and the practical tree work calendar

The nesting bird season stops vegetation clearance on most English sites between March and August, and the reason it stops work is narrower than most programmes assume. The offence under the Wildlife and Countryside Act 1981 attaches to a nest that is in use or being built at the moment of the works. It does not attach to a date. That means clearance in June is lawful if a competent check finds no active nests, and clearance in September is unlawful if a late brood is sitting in the hedge you are about to flail.

Contractors get this backwards in both directions. Some assume a blanket ban and lose four months. Others assume September is safe and take a call from the council's enforcement team.

What the 1981 Act actually protects

Section 1 of the Act makes it an offence to intentionally kill, injure or take a wild bird, to take, damage or destroy the nest of a wild bird while it is in use or being built, and to take or destroy its eggs. Species listed in Schedule 1 to the Act carry extra protection against disturbance while nest building, or while at a nest containing eggs or young. Barn owl and kingfisher are the two that come up most often on development sites.

Each nest and each egg can form a separate offence, which is why an incident involving a hedge is rarely a single charge. Company directors and individual machine operators can both be liable.

Councils have their own reason to care. The biodiversity duty in the Natural Environment and Rural Communities Act 2006 sits behind the conditions officers impose, and national planning policy expects harm to biodiversity to be avoided in the first place. An enforcement case over a destroyed nest also colours how the rest of your application is read.

Why March to August is a rule of thumb

The window written into most method statements runs from 1 March to 31 August. It is a sensible default for lowland England and it has no statutory force.

Real breeding activity spreads wider than that. Blackbirds and robins start in February in mild years. Wood pigeons nest almost year round. Tawny owls can be on eggs in January, and some species raise a third brood into September. Habitat matters as much as the date: dense bramble, ivy-clad trunks, conifer hedges and scrub all hold nests that are invisible from six metres away.

So treat the window as the period when a check is always needed, and treat the shoulder months as the period when a check is still worth doing. In practice, the extra cost of a September walkover is trivial against the cost of a stopped site.

Checks immediately before works

A nesting bird check is a walkover by an ecologist who looks for nests, and for the behaviour that indicates one nearby: birds carrying nest material or food, repeated alarm calling, adults flushing from the same point.

Timing is the part that gets diluted. The check should happen no more than 48 hours before clearance in that area, and many ecologists prefer to be on site the same morning. Birds build fast. A check three days before a start that then slips a week is worthless, and a condition worded around the start of development will not save you if a nest is destroyed.

Where clearance runs in phases, each phase needs its own check. Where the site holds hedgerows, scrub or mature trees with cavities, the ecologist should have the results of any Preliminary Ecological Appraisal to hand, because the same vegetation often carries bat and dormouse constraints that change the method entirely.

Records that demonstrate compliance

The evidence you want, if a complaint is ever made, is dull and specific.

• The date and time of each check, and the weather
• The name, qualifications and employer of the person who carried it out
• A plan showing the area checked and the area cleared
• Photographs of the vegetation before clearance
• A note of any nests found, the buffer applied and the date work resumed

Keep this with the site records rather than in an ecologist's inbox. Councils discharging a clearance condition will usually accept a short signed return with the plan attached, and the same pack answers a neighbour's complaint without a site visit.

An illustrative example. A developer clearing a boundary hedge in May instructed a check on the Friday, then lost the machine to another job until the following Wednesday. The re-check on Wednesday morning found two active nests in a 30 metre stretch. Clearing the rest of the hedge and coming back in July cost less than the delay would have done if the whole hedge had been left.

Working outside the season and what it does to the programme

The clean answer is to clear vegetation between September and February, which removes the check from the critical path and usually removes the ecologist from the site.

That is easy to say and often impossible to do, because the clearance date is set by the planning decision, the discharge of pre-commencement conditions and the finance drawdown rather than by the ecology. Where you cannot move it, two things help. First, separate vegetation clearance from the main groundworks package so that clearance can be done opportunistically in a window that opens. Second, price the risk properly: a standby cost for a delayed hedge costs less than an unplanned four-week hold.

Clearance before an application is submitted carries its own problem, since removing the constraint does not remove the policy consequence, which is the point covered in clearing a site before you apply.

Method statements and the conditions that require them

Councils commonly condition a vegetation clearance method statement, either on its own or within a Construction Management Plan. A workable statement names the clearance window, the check protocol, the buffer distances, the person responsible and the reporting route.

Keep it short and make every clause testable. "Clearance will be undertaken sensitively" is not a clause. "Clearance between 1 March and 31 August will follow a check by a suitably qualified ecologist within 48 hours of works starting in each compartment" is.

Where trees are being retained rather than removed, the protection measures come from the tree survey and its recommendations, and the two documents need to agree with each other on which trees are going.

If a nest is found

Stop work in that compartment. Do not try to move the nest, and do not attempt to make the adults leave.

The ecologist marks an exclusion zone, sized for the species and the disturbance involved, and work continues elsewhere. Typical buffers run from a few metres for a common passerine in a hedge to a much wider zone for a Schedule 1 species, where the ecologist's judgement and any licensing position govern. The zone stays in place until the young have fledged and the ecologist confirms the nest is no longer in use.

Then check again before resuming, because a second brood may follow in the same structure.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. Ecological survey, mitigation and licensing must be carried out by suitably qualified and, where relevant, licensed ecologists, and an AI-assisted draft is a starting point for that professional rather than a substitute.

To see which ecology and tree documents your site is likely to need before clearance begins, start with your site postcode on PlanScope.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.