Executive summary

The proposed policy is to achieve a 20% Net Gain in Biodiversity with a focus on the use of the Defra metric. However, species specific measures including nest boxes for cavity-nesting bird species, such as swifts, which are Red Listed and in significant decline, do not count in the Defra metric. Government guidance in the NPPG and the National Model Design Code, as well as several authorities, including RIBA and NHBC, support the installation of nest boxes in new developments as a low cost and effective way of achieving biodiversity gain (detailed references below).
As nest bricks are not included in the DEFRA BNG metric, they need to be included in the policy. We strongly suggest that the ‘Biodiversity and geodiversity’ Policy in the new Local Plan should include some specific wording to reference what other measures, including those for species inhabiting the built environment, will be used to assess biodiversity gain – mentioning swift boxes and bat boxes, as in the text of the ‘GC LP First Proposals’ document:
‘Nest boxes designed for swifts will also be suitable for starlings, house sparrows and tits, and will provide a low-cost way of achieving significant net gain in biodiversity’
At least a 1:1 ratio of nest bricks to dwellings is generally accepted now as good practice, with separate provision for bats depending on the characteristics of the site.

Biodiversity net gain

We have concerns that with the focus on the Defra metric for calculating biodiversity net gain, which is based only on green habitats, there is a danger that important biodiversity opportunities for species with measures such as nest bricks, roosting bricks, hedgehog highways etc may be given less emphasis or be overlooked completely. It is not clear in the ‘Policy Direction’ of the ‘Biodiversity and geodiversity’ part of the First Proposals’ document how such species measures are to be taken account of alongside the results of the Defra metric in assessing overall net gain in biodiversity. Given that much of the development in Greater Cambridge is in more ‘urban areas’ either within Cambridge City or new towns such as Northstowe then we believe these urban species are an important part of bringing nature close to people and an effective way of helping our declining wildlife.
We welcome the recognition of this in the text of the ‘GC LP First Proposals’ document on page 169 under the heading ‘Why is this policy needed’:
‘The focus for biodiversity enhancements is intended to be within the boundary of a site, and could include providing wildlife areas, trees, or smaller measures such as including bat or swift boxes’
Government guidance

The significance of species-specific measures in biodiversity net gain is emphasised by Government Guidance on the NPPF issued on 21 July 2019 (see below):
https://www.gov.uk/government/news/brokenshire-orders-house-builders-to-protect-wildlife
https://www.gov.uk/guidance/natural-environment
Paragraph 23 of this Guidance headed 'How can biodiversity net gain be achieved?' includes at the end of the first sub paragraph 'Relatively small features can often achieve important benefits for wildlife, such as incorporating swift bricks and bat boxes in developments and providing safe routes for hedgehogs between different areas of habitat.'

The recently published National Model Design Code: part 2 - guidance notes (20/07/21) also makes reference to bat and bird boxes and bird bricks. In Section N.3 Biodiversity, page 25: "Integrating Habitats: Biodiversity can be enhanced through facilitating habitats and routes for wildlife, for example, incorporating trees, wildflowers, ponds, bat and bird boxes, bee and bird bricks and hedgehog highways."

https://www.gov.uk/government/publications/national-model-design-code

The case for nest boxes

Swifts in the UK are on the Birds of Conservation Concern (BoCC) Red List and are classified as Endangered on the IUCN Red List assessment of extinction risk for Great Britain. Their numbers declined by 58% between 1995 and 2018, and by 41% in just 10 years up to 2018, that is over 5% per annum! Sparrows and starlings are also Red Listed in the UK.

The decline of birds such as swifts, which have nested for generations in older houses in holes and cavities under the eaves and in walls, is highlighted in a recent report – the Environment Agency, Chief Scientists Group (2021) The state of the environment: the urban environment:

The state of the environment: the urban environment - GOV.UK (www.gov.uk)

Loss of nest sites in older buildings is thought to be a significant factor in their decline and many new houses have been built with no new nest sites incorporated. Bird and bat boxes are relatively cheap, easy to integrate into new builds (generally as swift or bat bricks) and are sustainable needing no ongoing maintenance. Also, swift bricks successfully cater for other bird species such as house sparrow, starling, blue tit, great tit and house martin and can be considered as a ‘universal nest brick’, in numbers equal to the number of dwellings, as noted in:

https://cieem.net/swift-bricks-the-universal-nest-brick-by-dick-newell/

Support for incorporation of nest boxes in new developments
The Royal Institute of British Architects (RIBA) in: Gunnell, K., Murphy, B. and Williams, C., Designing for Biodiversity: A technical guide for new and existing buildings, RIBA Publishing & Bat Conservation Trust (2013).
An excellent recent report produced by the NHBC Foundation from a collaboration between the RSPB and Barratt Developments gives significant guidance on these issues on page 42 onwards, which includes providing nest sites (nest bricks) at a ratio of one per dwelling.
NHBC Foundation, Report NF 89, ‘Biodiversity in new housing developments: creating wildlife-friendly communities’ (April 2021). Available at:
Biodiversity in new housing developments: creating wildlife-friendly communities - NHBC Foundation
An expected new British Standard, BS 42021, ‘Biodiversity and the built environment: Specification for the Design and Installation of Bird Boxes’ is expected to give box/brick specification and a level of installation in new builds in line with current good practice.
(Proposed publication start date 07/02/22)
https://standardsdevelopment.bsigroup.com/projects/2017-03102#/section

Current good practice for nest boxes – Planning Authorities

The 1:1 ratio of nest bricks to dwellings was first outlined in the award-winning Exeter City Council Residential Design Guide SPD (2010). A number of planning authorities have adopted similar guidelines – for example Oxford, Cornwall, Brighton and Plymouth and South West Devon.

Within the OxCam Arc, Oxford City Council are leading the way with guidance on this issue. The recent Oxford City Council Technical Advice Note 8 entitled ‘Biodiversity – Planning Application Guidance’ gives an ‘expected provision’ of bird nest sites for building dependent birds’ at a rate of 1 per house and 1 per 2 flats, with separate provision for ‘bat roost sites’ at a rate of 1 per 5 houses and 1 per 10 flats.

https://www.oxford.gov.uk/info/20067/planning_policy/745/planning_policy_-_technical_advice_notes_tan

Case studies
The Duchy of Cornwall adopted the same principle of one nest site per dwelling in 2015, and a good example of the provision of a general type of integral box for all cavity nesting birds is the Nansledan development in Newquay:

https://www.rspb.org.uk/our-work/rspb-news/news/stories/the-duchy-of-cornwall-giving-swifts-a-home/

Our own local projects with developers (e.g., Taylor Wimpey and Hopkins Homes) at Northstowe, Cambourne West, Melbourn and elsewhere indicate an increasing willingness to engage with integral nest box projects already acknowledged in 2021 by clear environment strategies:
https://www.taylorwimpey.co.uk/corporate/sustainability/environment-strategy
Significant success has already been achieved in Cambridge and surrounding villages with substantial new swift and sparrow colonies established.
An example from Poland also demonstrates the effectiveness of nest boxes:
https://link.springer.com/content/pdf/10.1007/s10531-021-02334-0.pdf

In conclusion
We strongly suggest that the ‘Biodiversity and geodiversity’ Policy in the new Local Plan should include some specific wording to reference what other measures, including those for species inhabiting the built environment, will be used to assess biodiversity gain – mentioning swift boxes and bat boxes, as in the text of the ‘GC LP First Proposals’ document.
Submitted on behalf of:
Action for Swifts; Fulbourn Swifts; Over and Swavesey Swift Conservation Project 2020