Wintering bird surveys, sometimes known as non-breeding bird surveys, are an important part of assessing the ecological impact of a proposed development, where legal protections and conservation requirements are in place. Several factors influence the need for such surveys:

1. Type of Development 

• Large-Scale Projects: Infrastructure projects (roads, housing estates, wind farms, etc.) may have more significant impacts, increasing the likelihood of a survey.

• Energy Developments: Wind farms, solar farms, and other energy developments can disrupt migratory patterns or habitat use, necessitating detailed surveys to assess collision risk and/or habitat loss.

2. Location of the Development  

• Proximity to Designated Sites: If the proposed development is near or within protected sites (e.g., Special Protection Areas (SPAs), Sites of Special Scientific Interest (SSSIs), Ramsar sites), it is more likely that non-breeding bird surveys will be required, as these areas often support important wintering bird populations. The proximity of such sites is often determined through the completion of a desk-based study, which often includes contact with the Local Records Centre and / or a search of the Government’s multi-agency website ‘MAGIC’.  When assessing the potential impact of a development on a protected site, a Zone of Influence (ZoI) is utilised to determine how far-reaching development impacts might be. The size and nature of these ZoI can vary based on the characteristics of the protected site, the bird species, and the type of development. It is important to note that some potential development sites, although not within the immediate vicinity of a protected site, may support habitats that can be of importance to the species for which protected site designations exist. This is known as functional linkage. For example, a site that lies over 15km upstream of the Severn Estuary, but which contains habitats known to support qualifying species is likely to be ‘functionally linked’ to the SPA / Ramsar site, and in turn should be subject to the necessary non-breeding bird surveys. As such, as a general rule of thumb, it may be considered appropriate to apply a ZoI of 20km when deciding on whether non-breeding bird surveys are likely to be required. We have recently completed surveys and assessments for sites in the ZoI of The Severn Estuary, Thames Basin Heaths and Chew Valley.

• Habitats Present: Certain habitats, including (but not limited to), wetlands, estuaries, coastal areas, and open farmland, are more likely to host significant wintering bird populations. Development on or near these habitats may trigger the need for surveys. 

3. Size and Scale of Impact

• Extent of Habitat Loss or Alteration: The amount of habitat that could be lost, fragmented, or otherwise affected by the development is a crucial factor. Developments can disrupt feeding, roosting, or sheltering areas, directly impacting non-breeding birds. 

• Indirect Impacts: Noise, light pollution, and increased human activity may disturb birds, and introduce more predatory pressure (e.g. cats), and detailed surveys must be undertaken to understand the potential impacts on displacement or behavioural changes. Survey results will additionally help inform suitable and necessary mitigation strategies.

4. Historical Data and Local Knowledge 

• Previous Survey Results: If past surveys or local records (gathered as part of an initial desk-based study) indicate the presence of important wintering bird species and/or assemblages in or around the proposed development site, surveys may be required to update information or address potential changes.

• Local Bird Groups and Stakeholders: Feedback from local birdwatchers, county bird recorders, conservation organisations, or stakeholders can also influence the requirement for surveys.

5. Species Presence and Importance 

• Protected Species & Species of Conservation Concern: If your proposed development site or the surrounding local area is known or suspected to support legally protected (i.e. Schedule 1 Species), and/or species of local importance (e.g. species listed in the UK Biodiversity Action Plan, Red / Amber Listed Birds of Conservation Concern, or species highlighted as local conservation priorities (i.e. as determined through the development of local nature recovery strategies)) a survey will likely be required. The presence of species such as waders, geese, swans, raptors, and assemblages of farmland bird species which rely on specific conditions in winter, are potential key species considerations. For example, a local records search for a site earmarked for potential development has identified historic accumulations of large numbers of farmland bird species within the local area (e.g. c.1,000 linnet, mixed finch flocks including greenfinch, and good numbers of yellowhammer and corn bunting (all Red-Listed species)). The site is likely to be of significant value for these declining species, and surveys must be undertaken to establish what species and numbers the site supports, and to what extent (e.g. is it part of a wider network of suitable habitat, or is it isolated in its importance). Surveys will help determine what suitable conditions, land management practices, and / or habitats are providing importance, all of which can be utilised to establish a robust mitigation strategy to support development of the site.

• Winter Conditions: It should be noted that severe weather conditions in winter can increase the importance of certain habitats as refuges for birds in certain years, thus raising the importance of assessing the potential impacts of development during these times. For example, a particularly harsh winter may increase some species reliance on farmland crops (and / or specifically planted cover crops / supplementary feed) during the hunger gap. Assessment of sites during these times is considered particularly useful as it may help better direct specific mitigation and / or enhancement strategies.

6. Legal and Policy Obligations 

• Environmental Impact Assessment (EIA): Depending on the size and potential impact of the development, it may fall under EIA regulations, which would likely require detailed ecological surveys, including for wintering birds.

• Planning Policy: Local planning authorities may have specific requirements for bird surveys in their guidance or Local Development Plans, especially in areas with high biodiversity importance.

Conclusion

Considering these factors will help determine the need for non-breeding bird surveys as part of any proposed development. 

It is important to note that non-breeding bird surveys can take on a number of different forms (e.g. daytime walkover surveys, nocturnal bird surveys (suitable as a method to establish winter wader distribution and site use, and / or site use for roosting and foraging (e.g. certain geese species / farmland bird species), and wetland bird surveys utilising vantage point techniques), and must be undertaken by suitably competent ornithologists between November and March.

Our in-house ornithology team are equipped with a wealth of knowledge and experience and make use of top of the range equipment to ensure our surveys are conducted expertly and in accordance with industry standard guidance.

For further information contact:

Laura Grant BSc (Hons) MCIEEM

Associate Director, Ecology by Design Ltd

Tel: 01865 893348

Mob: 07495 002130

laura@ecologybydesign.co.uk