Biodiversity
Birds, Bats and Buildings
Many species of birds and bats are declining in numbers throughout Britain, and one of the key factors affecting their survival is the lack of suitable sites where they can successfuly nest, roost, hibernate and rear their young.
This document gives practical guidelines for builders, developers and renovators about the law, planning regulations and where to find further more detailed information.
Key Facts
- Wildlife in Buildings
- Investigation Stage
- Law and Planning
- Design Stage
- Design features for Birds
- Design Features for Bats
- Suppliers
Birds, Bats and Buildings
A Guide for Builders, Developers and Property Owners
Wildlife in Buildings
Many species of birds and bats are declining in numbers throughout Britain, and one of the key factors affecting their survival is the lack of suitable sites where they can successfully nest, roost, hibernate and rear their young.
Birds
Several bird species including house sparrows, starlings, barn owls, swallows, house martins and swifts regularly use buildings in which to nest. The last three species are almost completely dependent on built structures.
Bats
There are 17 species of bat found in England of which 14 are regularly found in buildings. Of these seven are almost entirely dependent on buildings for summer roosts including the common pipistrelle, soprano pipistrelle, brown long eared, serotine, lesser horseshoe, greater horseshoe and Natterer?s bats.
Greater horseshoe bat hanging in roof space
Wildlife can be a selling feature for a property as more members of the general public are becoming enthused about nature, for its own sake and as part of the wider sustainable development agenda
- Research linked to the BBC SpringWatch series estimates that approximately 30 million people are interested in wildlife and at least 14 million take part in a conservation activity.
- BBC Spring Watch research also revealed that 67% of people in the UK would like to see 'wildlife oustside their back door'
- The Royal Society for Protection of Birds has over 1,000,000 members
- The Wildlife Trusts have over 670,000 members
- Bird food for bird tables is now a multi million pound market in the UK
The Investigation Stage
Initial investigation must establish whether nesting birds or bat roosts are present on site, before starting on the design stage ? this can prevent much costly work later in the process. Many property owners and occupiers will be unaware of bats or birds on their properties. Any structure is a potential bat roost - the smallest bats can enter a gap just 8mm wide. While some bat species use lofts, for instance brown long-eared, greater and lesser horseshoe bats, others use very confined spaces such as behind hanging tiles, soffits, barge boards, under roof felt, in cavity walls, under wood cladding, behind window sills or inside sash windows. Some species prefer old properties, but bats can also be found in new buildings. Certain types of buildings are particularly suitable for nesting birds and bat roosts, for example old agricultural barns.
It is essential to ensure that surveys:
- Of nesting birds take place in summer
- Of bats take place in summer and / or winter, depening on type of bat roost
- Of bats are carried out by a suitable qualified and experienced person as it is illegal for anyone without the appropriate bat licence to enter a known bat roost or to capture and handle bats
NB: A bat licence may be required to carry out development works if a bat roost is present. Further information is available from Natural England Wildlife Management and Licensing.
Tel: 0845 6014523 (local rate).
Natural England
Suggested search technique for bats
Enquire if the house occupier is aware they have bats, or if bats have ever been found
Listen for chittering noise in warm weather, and by shining light along roof ridge beams, over stone and brickwork.
Look for evidence of droppings, particularly beneath ridge, the junction between two ridges, down hips and over bays, around chimneys, gables and all around the eaves.
During summer months, check for droppings sticking to window panes, outside walls, on window ledges and on ground beneath gable apex.
Natterer's bat roosting in brick space
It is very unlikely that the presence of bats or nesting birds will prevent the proposed building works but their requirements will need to be incorporated into the design from the beginning and work may need to be scheduled around bird or bat occupancy. It is important that all the relevant survey information is submitted with any planning application. There are circumstances when a planning application will not be considered valid without an ecological assessment. For further information see Cotswold District Council website, Validation Checklists for Planning and Associated Applications
Cotswold District Council
For advice on how to find a suitable ecological consultant
Cotswold District Council
In brief: The law
Wild Birds
It is an offence to intentionally or recklessly kill, injure or take any wild birds, take, damage or destroy its nest while in use or being built, and/or take or destroy its eggs, with a few limited exceptions. For full details of law see RSPB website
RSPB
Bats
All bats and structures used as bat roosts, whether the bats are present or not are protected by law. Disturbance of a bat roost without consultation with Natural England could lead to £5,000 fine per offence or even a six month sentence.
For details on bat law
Bat Conservation Trust
In brief: Planning Policy Statement 9
Paragraph 16 states that in addition to those species protected by the law, those species listed as "of principle importance for the conservation of biodiversity in England" should be protected during development and failure to do so may provide grounds for refusal of planning permission.
Paragraph 14 requires local authorities to encourage developers to maximise the opportunities for enhancing biodiversity in new developments .
Further information
- Planning Policy Statement 9, Biodiversity and Geological Conservation
- Circular 06/05: Biodiversity and Geographical Conservation - Statutory Obligations and Their Impact Within the Planning System.
- Planning for Biodiversity and Geological Conservation: A Guide to Good Practice
The Design Stage
The architect or designer brief should include the requirement to retain and enhance features for wildlife at the start of the project; this will maximise opportunities to create such features as retro-fitting which are always more expensive and time-consuming; for example it will ensure that the thermal integrity of the building is maintained and there is no risk to any warranties becoming void by placing holes in the wrong place.
In some circumstances, for example, where a bat roost is present, it is very unlikely that planning permission will be granted unless full details are submitted as to how wildlife will be retained on site as part of the planning application.
The incorporation of wildlife features may also help with obtaining planning permission, as paragraph 14 of PPS 9 requires planning applications for new developments to integrate biodiversity into the design of new buildings.
Sometimes planning permission is granted subject to planning conditions. Applicants should submit full information on the type, number and location of the artificial bird nesting and bat roosting sites that are to be installed and ensure that they are actually installed before the development is occupied.
Sample Planning Conditions for Bird and Bat Provision
No development shall take place until details of the provisions to be made for artificial bird (in particular species) nesting sites/boxes and artificial bat roosting sites/boxes have been submitted, and approved by the LPA. The approved works shall be implemented in full before the development is first brought into use, unless otherwise agreed in writing by the LPA.
Reason: To ensure that bird and bat species are protected and their habitat enhanced, in accordance with the Wildlife and Countryside Act 1981 as amended, the Conservation (Natural Habitats, &c.) Regulations 1994 and policy 9 of the Cotswold District Local Plan 2001 ? 11 Revised Deposit (as modified).
Proposals not requiring planning permission
There are many types of building work which do not require planning permission, but where the legislation on wildlife still applies. ie:
Timber treatment. Avoid using timber preservation control when nesting birds are present (March-August), as the fumes in a confined roof space can kill them. Bats are extremely sensitive to chemicals and in the past large numbers have been killed by organochlorine insecticides such as lindane although there are now a number of modern insecticides and fungicides, that after consultation with Natural England, can safely be used in spaces used by bats.
Birds Bats and Buildings Insecticides.
Loft Insulation. Loft insulation work, whether new or upgrading, should not prevent birds or bats gaining access at the eaves. The insulation material pushed into the soffit and fascia area can obstruct entry points and impede ventilation and therefore increase humidity in the roof.
For further information, see the JNCC website,
3rd Edition Bat Workers' Manual (2004) Mitchell-Jones, AJ & McLeish, AP.
Joint Nature Conservation Committee
Design Features for Nesting Birds
The type of artificial nesting sites which should be incorporated for birds is evidently dependent on the type of species already present or which you wish to attract. It is crucial that these artificial nesting sites reflect the type of nest used by birds elsewhere, and they can be either be purpose built or "off the peg".
Hole nesting species
Swift
Swifts feed, sleep and even mate in the air and are also entirely dependent on buildings for nest sites Modern building methods and regulations, redevelopment and maintenance of old buildings often exclude swifts from their nesting places. Swifts prefer to nest at least 4m above the ground with a clear flight path with no obstruction from trees or other buildings. Nest sites can be provided by opening up or incorporating slots and holes into the eaves to allows birds to nest just inside on top of the closed cavity, the solid brickwork ledge or within the soffit board. Swifts are clean, leaving few droppings. Swifts require a 'letterbox' entrance 65mm by 30mm which will deter access by sparrows.
Click on image for more detailed view
Swift sofit construction c. Jake Alsop / RSPB
Example
The Pilgrim Trust in Bedford which now owns the council's housing stock provided access 'slots' at intervals in uPVC boxed soffits. Having the full support of house owners, it resulted in a net increase in the number of nesting swifts.
Purpose made wood or woodcrete nest boxes can be incorporated into the eaves or purpose made bricks can be built into the structure during construction or restoration to provide sites for colonies. In some European buildings swift boxes are included as architectural features.
Further information
Starling and house sparrow
Although once common, both these species are declining and provision of nest sites can be of significant benefit. Both species typically nest in the eaves and this can be encouraged by the creation of appropriate sized holes. Depending on the design of the eaves, the aim should be to create a small hole to allow access for nesting birds but to prevent them being able to access to the roof void.
House sparrows require a minimum gap of 32mm while starlings need a minimum of 45mm to allow access.
Sparrow terrace, from Alana Ecology, (www.alanaecology.com)
Further information
RSPB
Eaves nesting species
House Martin
House martins traditionally build their own nest out of mud under the eaves but can also be encouraged to do so by the provision of artificial nests which sit beneath the eaves. These need to be carefully located to ensure droppings do not fall on windows, doors or paths below. At the Lower Mill Estate in the Cotswold Water Park over 70 artificial house martin nest boxes have been installed which after only three seasons have nearly 30 breeding pairs.
Artificial house martin nest boxes, Lower Mill Estate, near Somerford Keynes, Glos.
Further information
RSPB
Ledge nesting species
Pied wagtail, spotted flycatcher, kestrel, peregrine falcon
These species will use appropriately placed ledges (with a small lip around the edges) behind drain pipes, under eaves or secured corners. Care needs to be taken to ensure they are protected from the elements and predators but that they do not impact on the function or appearance of the building.
Barn/shed/garage nesting species
Swallow, pied wagtail, robin, barn owl
These will all nest in barns and out buildings, but they all have their own specific requirements. Barn owl nest boxes can be incorporated into a loft or roof design, by leaving an external access in a gable end. Swallows require open access into buildings and will build their own nests against rafters but will also use artificial nests. Open fronted garages, wood stores etc are ideal for swallows; however where these structures are required to be locked a high level access can be designed into the doors or end walls.
Further information
RSPB
Lincolnshire Wildlife Trust factsheets
External nest boxes
Robin, blue tit etc
There is a wide range of boxes to suit a number of different species which can be fixed to the outside of buildings. They should be fixed securely and if there is no natural shelter, it is best to mount the box facing somewhere between south-east and north, to avoid direct sunlight. They should also be located away from boiler flues and out of reach of predators, such as cats. Woodcrete nest boxes, although more expensive than traditional wooden boxes last longer and can be coloured to blend with the building materials.
Further information
British Trust Ornithology
Design Features for Bats
Existing buildings
When retaining roost sites in existing buildings it is important to consider the roost requirements of the species already using the site and the location of the current roost sites. Advice should be sought from an appropriately qualified and experienced ecological consultant in order to ensure that planning permission can be granted and that a bat licence will be achievable.
New Buildings
Roost sites for bats can easily be incorporated into new buildings and requirements for bats should be included in the architect's brief. There are many ways of enhancing the building for bats, for example:-
- Bat bricks in the external walls
- Bat boxes incorporated into the eaves
- Purpose built bat lofts, with access bricks or tiles
- Specially designed roof tiles, wooden cladding etc.
Evidently all these features are also relevant for retro-fitting to existing buildings. Artificial roosting sites can either be purpose built or ?off the peg?. Incorporating features for bats in a new build is an expanding field and there are significant opportunities for developers, architects and builders to become market leaders.
For more information and a review of the success of bat boxes in houses, see the following links:
Bat Conservation Trust report on the Scottish Natural Heritage website Scottish Natural Heritage
Focus on Bats, Natural England
Living with Bats - Bat Conservation Trust
Bats in Buildings: a guide for building professions, Scottish Natural Heritage
Timing of Works
Bats are most vulnerable during the summer, when large numbers may be gathered together to breed and young bats, unable to fly, may be present . Building work can result in the total loss of bat roosts and disturbance to or death of the bats, unless works are correctly timed and planned; although the loss of the roost is sometimes unavoidable.
- Works to known breeding sites should be avoided between the months of May and August.
- Conversely works to winter roosts should be avoided between October - March
- Advice should be sought from an ecological consultant and / or Natural England
- If bats are found during building works, works should be halted immediately
Without a licence, it is illegal to kill, injure, capture or disturb a bat, or to damage its roosting place.
Monitoring
Local voluntary bat group workers should be invited to help monitor the success or failure of new structures for bats.
Gloucestershire Bat group Chairman: Maurice Febry 01242 242160
Cotswold Water Park Bat Group Gareth Harris 01793 752413/752730
Bat Helpline: 0845 1300 228 (local rate)
The National Bat Helpline was set up to provide information for all of those who come across bats and throughout the year it provides advice to householders, builders and teachers. Thousands of bats are conserved each year through this advice service.
General Design Rules for Wildlife
- Be clear on what species of wildlife you are trying to retain and enhance on the development site, as they will all have different requirements.
- Use professional ecological advice and local knowledge to target particular species of bats and birds.
- If more than one species happens to take up residence of their own choice, they will soon find space to live alongside each other.
In descending order of importance the criteria for safeguarding existing bird nest sites/ bat roost sites or creating new ones:-
- Leave existing holes alone when carrying out repairs and renovations
- Make new holes to retain access to existing roost/nest sites close to original location
- Use existing internal spaces to make new roost/nest sites
- Utilise the existing roof or fascia/soffit design to create new roost/nest sites
- Create new internal spaces during new build or refurbishment
- Integrate bat brick/nest brick into the design.
- Integrate living walls on external wall to provide natural nesting sites and structure to attach roost or nest boxes.
- Use externally fitted bat boxes/nest boxes.
Green walls
On buildings where fitting external nest boxes or bat boxes is not possible, one option is to position an external structure such as a pagoda or large structure against a wall. Nest boxes can be incorporated into the design or affixed to these structures. Fast growing climbers can be used to hide structures and nest boxes , provide external insulation as well as colour, invertebrate food and natural nesting sites.
Biodiversity by Design
Bat box sited on 'green wall'
Green/living Roofs
Feeding habitat may be limited by the lack of green space. The creation of living/green roofs can create feeding areas , enhance biodiversity, reduce heating costs, reduce the rate of water run off and provide attractive views from overlooking buildings.
Living Roofs
Landscape Design
The design of the landscape around the development is also very important in ensuring the success of any retained or created nesting and roosting sites.
- Native plants will encourage invertebrates, thereby providing food for some bird species and bats; berry producing shrubs will provide food for birds
- Hedges will act as flightlines for bats
- Trees around bat access points will provide cover
- Ponds will encourage invertebrates
Further Information
Neighbourhoods Green
Mayor of London - Building Green
Commission for Architecture and the Built Environment
Bats in Churches
Download documents:
Birds Bats and Buildings list of suppliers, pdf 75kb
Birds Bats and Buildings approved Insecticides, pdf 12kb
Images of Bat boxes, roosts etc, pdf 300kb
Images of Bird boxes, nests etc, pdf 333kb
