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Development advice

Birds nest in a range of habitats including trees, scrub, grasslands and cliffs. Man-made structures such as quarries, buildings and derelict walls also provide nesting opportunities. Therefore, many types of development can affect birds, from upland wind farms to town centre regeneration. Planning authorities often ask developers to assess a plan’s effects on birds and mitigate for it.

Different development situations need different ornithological survey techniques, and different mitigation and compensation approaches. The following information is applicable to all developments. However, specific assessment is needed for some large developments or those close to protected areas. 

Planning permission does not override the Wildlife and Countryside Act (WCA). Therefore even if there is planning permission, development sites will need to be assessed in advance by a suitably qualified ecologist and mitigated for accordingly. This applies if it has qualifying bird habitat features such as trees, woodlands, scrub, grassland and hedgerows.

The Wildlife and Countryside Act 1981 (WCA) as amended protects birds as well as their nests and eggs. This makes it an offence to intentionally or recklessly damage or destroy an active bird’s nest or any part thereof. Schedule one birds under the WCA have extra protection.

Under the WCA, actions that would otherwise be an offence regarding wild birds cannot be licensed for development purposes.

Schedule one bird species

Many rare birds are listed in Schedule One. These birds are provided with the normal protection given to all British birds. That is it is an offence to kill or injure our native birds, or damage or destroy their nests or eggs.

However in addition, Schedule 1 birds are further protected by it being an offence to intentionally or recklessly disturb:

  • such a bird whilst building their nest, or they are in, on or near a nest containing eggs or young
  • their dependent young

Where nesting Schedule 1 species are likely to be disturbed for a specific purpose you will need a licence from Natural Resources Wales.


The maximum penalty for non-compliance with the WCA for each offence in the Magistrates’ Court is a £5000 fine and/or six months imprisonment. Any equipment used to commit the offence may be forfeited. Both the company and the individuals can be held liable.

There isn’t always a need for a survey. While most buildings and development sites have some potential for nesting birds, some sites have greater potential than others. These include developments affecting woodland, hedgerows, waterbodies and scrub.

Guidance note two:

Where we deem there is insufficient risk of finding nesting birds for a survey, applicants’ and/or contractors’ responsibilities to the relevant wildlife law remains.

Most commonly, a survey for nesting birds will be needed for works in the main nesting season which is typically March to August. However, some bird species are known to breed outside this time. For example barn owls are known to nest throughout the year. An assessment will need to be made identifying the presence of active nests within the development site. Recommendations will then be made by the competent surveying ecologist to ensure that the development abides by the legal framework.

When it is considered unreasonable to request a survey to accompany the application, it doesn’t mean that nesting birds will not be present. If nesting birds are found during development, remember they are still protected under the WCA, and it is illegal to disturb them.

Generally, the presence of nesting birds can only delay development, but not prevent it.

Surveys may be needed if works that could disturb nesting birds and break the law are proposed for the nesting season. This would include works like vegetation removal or demolition.

Types of survey

The specific survey to be run will depend on the development’s likely impact. Often for larger or sensitive sites, an extended phase I habitat survey or similar initial ecology assessment will assess the site’s potential for birds. Then it will recommend additional survey work.

Breeding and wintering bird surveys are often undertaken for larger developments. There, it is necessary to provide robust ornithological baseline data which usually informs an Ecological Impact Assessment.

Breeding bird surveys and winter bird surveys are needed to assess the interest level and identify mitigation proposals.

The most common type of survey likely to be encountered will be the Breeding Bird Survey. This establishes breeding birds’ use. It can be carried out between March and August, but ideally between March and June in most years.

Surveys in March, April and early May, may also record migrating birds’ usage of the site.

A Winter Bird survey is run between November and February, and is usually for identifying over-wintering birds’ use of a site. Some of those birds such as swans, redwings and waxwings may not be present during summer, but still find sustenance on the site during winter. The survey period may be extended to September and October to record migrating birds.

Guidance note three:

The WCA does not define a bird’s breeding season. The law protects all active nests regardless of the time of year. Therefore, we expect applicants to seek suitably qualified ecological advice for timing work, and identify suitable mitigation measures to ensure compliance with the WCA.

To help avoid affecting nesting birds, we recommend that works should be done outside the nesting season, which is generally from March to August.

While ensuring avoidance of harm to nesting birds, conducting all work outside the nesting season may not be appropriate. Also these dates are only a guide as some birds will nest outside this period.

Alternatively, applicants can often ensure they avoid harm to nesting birds by showing there are no nesting birds at the site immediately before works start. This is done through a bird nesting survey by a suitably qualified ecologist. This survey should be submitted and agreed by the Local Planning Authority.

Guidance note four:

If at any time nesting birds are observed, works which may disturb them must stop immediately and advice must be sought. Any active nests identified should be protected until the young have fledged. Where a Schedule 1 species is involved, mitigation for effects such as the loss of a nesting site should be devised and implemented.

Some developments will have multiple features suitable for nesting birds. Then for compliance with laws and planning policies like Policy ENV 6 Bridgend LDP, a condition will be included to secure their long-term protection. This condition helps the local authority demonstrate its commitment to biodiversity conservation under Section 40 of the Natural Environment and Rural Communities Act 2006.

An authorised person, someone with the owner or occupier’s written consent, may fell or prune a dangerous tree to preserve public health and safety. If Schedule 1(3) birds would be affected, then a licence from Natural Resources Wales is required. Similarly a licence is also needed for tree work deemed necessary for reasons other than health and safety.

Accidental injury, killing or disturbance of a wild bird due to lawful tree use may not be an offence. That is provided it can be shown that the harm could not have been reasonably avoided.

Do not clear vegetation during the nesting season which is typically March to August.

Your site may have trees or scrub or other features important for birds. If they are to be lost to development, time the start of work to avoid conflict with birds’ and small mammals’ breeding seasons. This is the first step to preventing unnecessary distress and harm, or committing an offence.

As well as conducting works at the correct times of year, sensitive development design uses site assets as part of well-designed green infrastructure. This can help avoid disturbance to birds, and preserve potential nest sites for future years. Also, developments can enhance existing habitats for birds through landscaping schemes, and providing nest boxes.

When working on features like rooves, fascias, or soffits, please beware of nesting birds sharing our homes.

Building renovation, refurbishment and conservation are common development activities, particularly in urban regeneration areas.

Give special attention to any site clearance/development work affecting buildings, as this is where swifts, swallows, house martins and barn owls prefer to nest.

Large houses, farm buildings and historic buildings can provide important nesting and shelter habitats for several important bird species. Buildings also provide roosting opportunities for bats.

During development, many bird species of concern to conservation can be encountered. Among these are barn owls, house sparrows, starlings and swallows. Also, there are several other birds which are not of conservation concern but are legally protected at the nest, like finches and robins. If birds are nesting in a building, works should be scheduled to start outside the nesting season which is usually March to August inclusive.

Barn owls are the most commonly encountered schedule one bird species during development.

They nest in a variety of locations but prefer roomy, well-sheltered places. They tend to inhabit barns and old buildings usually in areas of open country containing rough, tussocky grassland. Over this land, barn owls hunt for their favoured prey which include short-tailed voles, mice and shrews. Such locations can be found very close to urban areas and so barn owls are not just seen in rural locations.

Disappearing habitat

In the last century, stone barns were often constructed with 'barn owl windows' to encourage the birds to nest. This helped to control rodents.

Old barns used by barn owls are disappearing from the countryside as a result of demolition and decay. Also, converting barns and derelict cottages has decreased sites. The Barn Owl Trust’s research has shown the negative effect of barn conversions, and also the usefulness of providing for barn owls.

Your barn conversion project

If you are running works such as a barn conversion, identify if barn owls or bats are using the site, or whether they used to. More information on barn owl surveys, legal considerations, planning issues, mitigation, enhancement, nest boxes and other accommodation is in the Barn Owl Conservation Handbook.

Barn conversions are never refused because of barn owls and the presence of barn owls can actually support a development with provision. This is because it can help secure the long-term future of the site for the species. Download a copy of the Barn Owl Trust’s latest guidance "Barn Owls and Rural Planning Applications: a Guide".

Trees are a potential habitat for many species of nesting birds. To avoid unnecessary harm and distress, works to trees should be done outside of the British bird nesting season which is usually March to August. If this is impossible, a qualified ecologist should make a detailed inspection of each tree immediately before the works.

Should an active nest be found whether it is being built, contains eggs or chicks any work likely to affect the nest must be halted. A working boundary of at least five metres should be left intact around the nest until becomes inactive. A greater buffer distance may be needed depending on the setting or the species and particularly if it is a schedule one species.

As with trees, hedgerow management should be timed to avoid the nesting season. If works cannot be completed outside of the season, some avoidance measures are available.

  1. Carrying out a nesting bird check before works. However it must be stressed, that this is a last-minute solution that could still delay works if nesting birds are found.
  2. Prevent the hedge from being used for nesting by covering the hedgerow with bird-proof netting before the nesting season starts in March.
  3. A suitably qualified ecologist must always assess the works. If implemented, the ecologist should implement the work or supervise it.

The mitigation needed to reduce a development’s negative effects on birds will vary according to a site’s size and nature, and the particular species there. Your chosen ecologist will be able to advise on the site’s mitigation needs. Key mitigation measures could include:

  • protecting areas containing nesting birds such as trees or hedgerows
  • maintaining a corridor of natural vegetation onsite
  • creating new habitat suitable for the species using the site or close by
  • timing works outside the nesting season
  • undertaking construction activity only during daylight
  • not developing right up to the edge of watercourses/waterbodies

Some mitigation measures may need an ecologist to confirm that all the procedures have been followed.

As with mitigation requirements, compensatory measures will depend on the site’s size and nature, and the needs of the species which use or used it. A net-gain approach should be employed when planning any compensatory measures. This ensures that we address the current issues affecting our birds and wildlife in general such as habitat loss. Also it covers any failures in new habitat creation such as unsuccessful tree planting.

While we are committed to protecting and enhancing biodiversity and landscape resources, there will likely be occasions where loss is unavoidable. To avoid incremental loss across the county borough, even small amounts of habitat should be replaced. This should be either onsite where design allows in a green infrastructure approach or off-site as part of biodiversity off-setting in agreement with a landowner.

Occasionally, a well-thought-out scheme can actually increase a site’s level of biodiversity and landscape quality above that which existed before development.

Several compensation options are available for the loss of habitats:

  1. On-site re-creation of habitats of equal or greater quantity to those lost.
  2. Enhancement of poor quality habitat on-site as when species-poor amenity grassland is turned into species-rich grassland.
  3. Off-site creation and/or enhancement of habitats. This is best undertaken in consultation with the Natural Resources Wales, Bridgend County Borough Council and local wildlife trusts.
  4. Financial contribution towards the creation, enhancement and/or management of off-site habitats.

On-site compensation

When recreating habitats on-site, it is important to understand the local context in which those habitats are being created. Some habitats are more appropriate to an area than others. Similarly, creating the right habitat can improve the ecological network’s overall connectivity and vastly increase the wildlife benefit. Guidance on incorporating wildlife habitats into developments through green infrastructure can be found in Section A: The Green Infrastructure Approach.

Some compensation measures are simple and can be achieved at little extra cost. The use of native berry bushes for landscaping schemes and gardens is a good example. Often it can improve on what was there originally in the case of some urban sites.

Large habitat losses will naturally need equally large compensation measures such as new woodland/scrub planting or the creation of new ponds. Expected large losses and subsequent compensation should be considered at the project and planning process’s very outset. This enables input from several sources about the most suitable and effective compensatory measures. Also it may identify off-site locations where biodiversity off-setting can be used as a compensation tool. Ideally this would be somewhere nearby for the greatest benefit.

Often habitat creation is driven by habitat loss. Yet in some circumstances, greater benefit can be gained by creating rarer or more specialist local habitats where the opportunity arises.

Off-site compensation

Replacing habitats offsite should always be a last resort and as much natural value as possible should remain onsite. This is not only for wildlife, but also for people living on or nearby the site. Green infrastructure provides numerous benefits and its removal could result in a loss of benefit and function for the local community.

However, we understand that in some cases the overriding need for development will conflict with our biodiversity goals. It isn’t always practical to completely replace habitats and green infrastructure within the development envelope. To address this, any loss must be replaced offsite.

All biodiversity off-setting should be undertaken in consultation with Natural Resources Wales, Bridgend County Borough Council and local wildlife trusts.

There are several ways to achieve this such as:

  • biodiversity off-setting including creation/enhancement/restoration offsite of habitat in arrangement with a landowner
  • contribution towards habitat creation/enhancement by other parties, such as the Wildlife Trust of South and West Wales

Off-setting produces the greatest benefit when habitat creation, restoration and/or enhancement occurs in close association with existing habitats. The larger the habitat patch and its connectivity to other habitats, the better for wildlife.

Enhancing existing habitats

One of the simplest ways to add biodiversity to a development is to enhance what is already onsite. This could be by creating a new pond, tree planting, repairing a hedgerow or changing grassland management on a site. With some larger developments, it is possible to create dedicated wildlife areas of grassland, woodland, scrub or even waterbodies.

Bird Boxes

Choosing and installing bird boxes is a relatively cheap and simple way of supporting wildlife for all scales of development. There are many different types designed to support different species such as house martins and sparrows. Many are maintenance-free, easy to install and, depending on materials, will usually last over 25 years. Some can be attached to buildings, and are designed to blend in.

Green/brown rooves

In some developments, it may be possible to include green/brown rooves on housing and garages which can benefit several bird species. Brown rooves are a simple, environmentally friendly way of recycling building materials onsite and creating a non-intrusive habitat for diverse species including black redstart.

When planning development in and near water, it is helpful to incorporate bird-friendly features like aquatic planting, nest holes and perching posts.

Image credit: 'Feeding the blut tit' by Tambako the Jaguar. Licence credit.

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