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Guidance on encountering Birds during the development process including regulations, requirements and actions in particular to protected species and their habitats.
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Birds nest in a range 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, from upland wind farms to town centre regeneration, can affect birds. Planning authorities often require developers to assess impacts on birds and to implement mitigation measures.

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


Planning permission does not override the WCA. Therefore, even if planning permission is in place, a development site with qualifying bird habitat features, such as trees, woodlands, scrub, grassland and hedgerows will need to be assessed in advance by a suitably qualified ecologist and mitigated for accordingly.


Birds (as well as their nests and eggs) are protected under the Wildlife and Countryside Act 1981 (WCA) (as amended). This makes it an offence to intentionally or recklessly, damage or destroy an active birds’ nest or any part thereof. Schedule 1 birds under the WCA receive additional protection.

Under the Wildlife and Countryside Act, it is not possible to licence actions that would otherwise be an offence in relation to wild birds, for the purpose of development.

Schedule 1 bird species

Many rare birds are listed in Schedule One of the WCA. These birds are provided with all the normal protection afforded to all British birds i.e. it is an offence to kill or injure our native birds, or damage or destroy their nest or eggs.

However, in addition, Schedule 1 birds are further protected making it an offence to intentionally or recklessly: disturb a such a bird whilst building their nest, or is in, on or near a nest containing eggs or young; or disturb dependent young of such a bird

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


The maximum penalty for non-compliance with 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.



Do I need to undertake a survey?

Not always. Whilst most buildings and development sites have some potential for nesting birds, some sites have greater potential than others, such as development affecting woodlands, hedgerows, water-bodies and scrub.


Where Bridgend CBC consider there not to be sufficient risk of encountering nesting birds to request a survey this does not remove the applicant &/or contractors responsibilities to adhere to the relevant wildlife legislation.

Most commonly a survey for nesting birds will be required if works are to be undertaken within the main bird nesting season, typically March to August. However, some species of bird are known to breed outside of this time; Barn Owls for example 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 proceeds in accordance with the legislative framework.

Please note that when it is considered that it is not reasonable 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 it is essential to remember that they are still protected under the WCA and it is a criminal offense to disturb them.

The presence of nesting birds can generally only delay development, not prevent it.

If works that could disturb nesting birds and result in a breach of legislation (e.g. vegetation removal, demolition) are proposed within the nesting bird season, surveys may be required.

The specific survey to be conducted will depend on the likely impact of the development. 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 and will recommend additional survey work.

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

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

The most common type of survey likely to be encountered will be the Breeding Bird survey, this is used to establish the use of the site by breeding birds, this survey can be carried out between March and August but ideally between March and June in most years. Surveys during March, April and early May, may also record the usage of the site by migrating birds. A Winter Bird survey as the name suggests is carried out between November and February and is usually to identify the use of a site by visiting over-wintering birds, some of which may not be present during summer but still find sustenance on the site during winter such as swans, redwings and waxwings. The survey period may be extended in to September and October to record migrating birds.

Timing of Works


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

To help avoid impacting on nesting birds Bridgend County Borough Council recommend that works should be done outside the nesting season, which is generally recognised to be from March to August.

Whilst ensuring avoiding harm to nesting birds conducting all work outside the bird nesting season may not be appropriate and these dates are a guide as some birds will nest outside of this period.

Alternatively, the applicant is often able to ensure they avoid harm, to nesting birds by demonstrating through a bird nesting survey by a suitably qualified ecologist that there are no nesting birds at the site immediately prior to works commencing. This survey should be submitted and agreed by the Local Planning Authority.


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

Some developments will have multiple features suitable for nesting birds. In such developments, to ensure compliance with the law and with planning policies such as Policy ENV 6 Bridgend LDP, a condition will be included to secure the longterm protection of the species. This condition will assist in demonstrating the local authority’s commitment to its statutory duty to conserve biodiversity under Section 40 of the Natural Environment and Rural Communities Act 2006.


An authorised person (i.e. someone who has the written consent or the owner or occupier), may fell or prune a dangerous tree in order 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 required for tree work deemed necessary for reasons other than health and safety.

Accidental injury, killing or disturbance of a wild bird, as a result of a lawful tree operation may not be an offence, provided it can be shown that the harm could not have been reasonably avoided.


If your site contains trees or scrub or other features important for birds and they are to be lost to development, timing the commencement of work so as not to conflict with the breeding season of birds and small mammals is the first step to avoiding unnecessary distress and harm and committing an offence. 

Do not carry out vegetation clearance during the nesting season! (Typically March – August)

As well as conducting works at the appropriate time of year, sensitive development design utilising the site assets as part of well-designed green infrastructure can help avoid disturbance to birds, preserving potential nest sites for future years. Developments can also enhance existing habitats for birds through landscaping schemes and nest box provisions.

When conducting works to roofs, facias, soffits etc. Please beware of nesting birds sharing our homes.

Birds and Buildings

Building renovation, refurbishment and conservation works are a common development activity, particularly in areas of urban regeneration.

Particular attention should be paid to any site clearance/development work affecting buildings, as this is where swifts, swallows, house martins and barn owls preferentially choose to nest.

Large houses, farm buildings and historic buildings can provide important nesting and shelter habitat for a number of important bird species. Buildings also provide roosting opportunities for bats.

Many bird species of conservation concern can be encountered during development. Among these are barn owls, house sparrows, starlings and swallows. In addition there are a large number of other birds which are not of conservation concern but are legally protected at the nest, such as finches and robins. If birds are found to be nesting within a building works should be scheduled to commence outside of the nesting season, March to August inclusive.

Barn Owls

Barn Owls are the most commonly encountered Schedule One species of bird encountered during development of buildings.

Barn Owls 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 areas of rough, tussocky grassland over which it hunts for its favoured prey; the short-tailed vole, mice and shrews.

Such locations can be found very close to urban areas and therefore Barn Owls are not just to be found in rural locations.

Did you know! In the last century stone barns were often constructed with 'Barn Owl windows' to encourage the birds to nest. This assisted in keeping rodents under control.

Old barns used by Barn Owls are disappearing from the countryside as a result of demolition and decay. In addition the conversion of barns and derelict cottages has also contributed to site loss. Research undertaken by the Barn Owl Trust has demonstrated the negative effect of barn conversions but also the usefulness of making provision for Barn Owls.

If you are undertaking works such as a Barn Conversion it is important to identify if site is being used by Barn Owls (and bats) or whether it used to be. More information on Barn Owl surveys, legal considerations, planning issues, mitigation and enhancement and nest boxes and other accommodation can be found in the Barn Owl Conservation Handbook (Barn Owl Trust, 2012).

Barn conversions are never refused because of Barn Owls and the presence of Barn Owls can actually support a development (with provision) as it can help secure the long-term future of the site for the species. You can download a copy of the latest guidance "Barn Owls and Rural Planning Applications - a Guide" published by the Barn Owl Trust with support from Natural England.

Trees and Birds

Trees are a potential habitat for many species of nesting birds. To avoid unnecessary harm and distress, works to trees should be undertaken outside of the British bird nesting season (March to August). If this is not possible then a detailed inspection of each tree should be undertaken by a qualified ecologist immediately prior to the arboricultural works.

Should an active nest be found (being built, containing eggs or chicks) any work likely to affect the nest must be halted and a working boundary of at least 5m left intact around the nest until the nest becomes inactive. A greater buffer distance may be required depending on the species (particularly if a Schedule One) and setting.

Hedgerows and Birds

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

  • Carrying out a nesting bird check prior to works. It must be stressed however, that this is a last-minute solution that could still delay works should nesting birds be found;
  • Prevent the hedge from being used for nesting by covering the hedgerow with bird-proof netting prior to the start of the nesting season (i.e. before the end of February);
  • The works must always be assessed by a suitably qualified ecologist. If implemented then the work should be carried out by or supervised by the ecologist.


The mitigation required to reduce any negative effects of development on birds will vary between the size and nature of a site and the particular species found to be using that site. Your chosen ecologist will be able to provide advice on the mitigation requirements of the site. Key mitigation measures could however include the following;

  • Protecting areas containing nesting birds, such as tree or hedgerows
  • Maintaining a corridor of natural vegetation on a site;
  • Creating new habitat suitable for the species using the site, on or close to the site;
  • Timing works outside of the nesting season;
  • Construction activities only during daylight hours;
  • Do not develop right up to the edge of watercourses/water bodies.

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


As with the mitigation requirements, compensatory measures will be entirely dependent on the size and nature of the site and the requirements of the bird species that were or are still using the site. A net-gain approach should be employed when planning any compensatory measures; this is to ensure that we are addressing the current issues affecting our birds and wildlife in general, such as loss of habitat. It is also there to cover any failures in new habitat creation such as unsuccessful tree planting.

Whilst Bridgend County Borough Council is committed to protecting and enhancing its biodiversity and landscape resource there are likely to be occasions where loss is unavoidable. To avoid incremental loss across the Borough even small amounts of habitat should be replaced, either onsite where the design allows (as part of a Green Infrastructure Approach) or off-site as part of biodiversity off-setting in agreement with a landowner.

In some cases a well thought out scheme can actually increase the level of biodiversity and landscape quality of a site above that prior to development.

A number of options are available in terms of compensation for the loss of habitats;

  • On-site re-creation of habitats of equal or greater quantity to those lost;
  • Enhancement of poor quality habitat on-site (e.g. species-poor amenity grassland into species-rich grassland);
  • 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;
  • 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 overall connectivity of the ecological network and vastly increase the wildlife benefit. Guidance on incorporating wildlife habitats through green infrastructure into developments 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 bearing bushes for landscaping schemes and gardens in development are a good example and can often improve upon what was there originally, in the case of some urban sites.

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

Often habitat creation is driven by habitat loss, but 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 off-site should always be a last resort and as much natural value as possible should remain on-site. This is not only for wildlife but also for people living on or nearby the site. Green infrastructure provides numerous benefits and its removal from a locality could result in a loss of benefit and function for the local community.

However, Bridgend County Borough Council understand that in some cases the over-riding need for development will conflict with our biodiversity goals and it isn’t always practical to completely replace habitats and green infrastructure within the development envelope. To address this any loss must be replaced off-site.

All biodiversity off-setting should be undertaken in consultation with Natural resources Wales, Bridgend County Borough Council and local Wildlife Trusts.

There are a number of ways in which this can be achieved:

  • Biodiversity Off-setting (creation/ enhancement/ restoration off-site) in arrangement with a landowner;
  • Contribution towards habitat creation/enhancement undertaken by other parties, such as the Wildlife Trust of South and West Wales.

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

New Benefits

Enhancing Existing Habitats

One of the simplest ways to add biodiversity to a development is to enhance what is already on the site. This could be in the form of creating a new pond, tree planting, repairing a hedgerow or changing the management of grassland on a site. On larger developments, sometimes it is possible to create dedicated wildlife areas of perhaps grassland, woodland, scrub or even water bodies.

Bird Boxes

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

Green/Brown Roofs

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

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

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