11. Offshore Ornithology

11.1. Introduction

  1. This chapter of the Array Environmental Impact Assessment (EIA) Report presents the assessment of the likely significant effects (LSE1) (as per the EIA Regulations) on offshore ornithology as a result of the Ossian Array which is the subject of this application (hereafter referred to as “the Array”). Specifically, this chapter considers the potential impacts of the Array on offshore ornithology during the construction, operation and maintenance, and decommissioning phases.
  2. The following technical chapters also inform the assessment presented in this chapter:
  • volume 2, chapter 8: Benthic Subtidal Ecology; and
  • volume 2, chapter 9: Fish and Shellfish Ecology.
  1. This chapter relies upon information contained within:
  • volume 3, appendix 11.1: Offshore Ornithology Baseline Characterisation Technical Report;

-        annex A: Offshore Ornithology Design-Based Abundance Estimates;

-        annex B: Offshore Ornithology MRSea Abundance Estimates;

-        annex C: Offshore Ornithology Colony Counts for Breeding Season Regional Populations;

-        annex D: Offshore Ornithology Apportioned Design-Based Abundance Estimates;

  • volume 3, appendix 11.2: Offshore Ornithology Collision Risk Model (CRM) Technical Report;

-        annex A: Offshore Ornithology Deterministic CRM Estimates;

-        annex B: Offshore Ornithology Migratory CRM Estimates;

  • volume 3, appendix 11.3: Offshore Ornithology Displacement Technical Report;

-        annex A: Offshore Ornithology Displacement Data;

  • volume 3, appendix 11.4: Offshore Ornithology MRSea Technical Report;

-        annex A: Offshore Ornithology MRSea Validation Methodology;

-        annex B: Offshore Ornithology MRSea and Design-Based Abundance Estimates Comparison;

  • appendix 11.5: Offshore Ornithology Population Viability Analysis (PVA) Technical Report.

11.2. Purpose of the Chapter

  1. The Array EIA Report provides the Scottish Ministers, statutory and non-statutory stakeholders with adequate information to determine the LSE1 of the Array on the receiving environment. This is further outlined in volume 1, chapter 1.
  2. The purpose of this offshore ornithology Array EIA Report chapter is to:
  • present the existing environmental baseline established from desk studies, site-specific surveys, numerical modelling studies and consultation with stakeholders;
  • identify any assumptions and limitations encountered in compiling the environmental information;
  • present the environmental impacts on offshore ornithology arising from the Array and reach a conclusion on the LSE1 on offshore ornithology, based on the information gathered and the analysis and assessments undertaken; and
  • highlight any necessary monitoring and/or mitigation measures which are recommended to prevent, reduce or offset the likely significant adverse effects of the Array on offshore ornithology.

11.3. Study Area

  1. Figure 11.1   Open ▸ illustrates the offshore ornithology study area for the Array which encompasses:
  • the Array (i.e. the area in which the wind turbines will be located);
  • a 4 km buffer around the Array (the Array Offshore Ornithology Study Area); and
  • an 8 km buffer around the Array (the Array Offshore Ornithology Survey Area).
  1. In addition, it is important to consider that ornithological receptors are highly mobile, travelling potentially long distances whilst foraging and on migration. As such, the Array has the potential to impact seabird populations over a much wider region. Consideration has therefore also been given to regional populations of seabirds that may have connectivity to the Array. The geographic spread of these regional populations varies according to biological connectivity, which differs between species and seasons, as detailed in volume 3, appendix 11.1. The regional Zone of Influence (ZoI) is therefore not a single, defined area, but a dynamic area over which the Array’s impacts may be felt according to the species and time of year.
  2. In the breeding season, the regional ZoI is defined as the area within the site- and species-specific foraging range recommended by NatureScot (2023c). For most species, this is the species’ mean-max + 1SD foraging range from Woodward et al. (2019), but in other cases the recommended foraging range is modified to take into account site-specific evidence.
  3. Outside of the breeding season, for most species the regional ZoI is defined as the season- and species-specific BDMPS region as described in Furness (2015). However, in line with NatureScot (2023d), a different ZoI is applied to guillemot and large gulls (herring gull, lesser black-backed gull and greater black-backed gull). For those species, the ZoI is defined as the same region as per the breeding season, on the basis of tracking data that indicates birds remain within the general vicinity of their breeding colonies. It should however be noted that the population present within the ZoI may differ between seasons (even if the ZoI itself is the same) as the result of different population structures (i.e. during the breeding season, prior to fledging juvenile chicks will not be present at sea) and the potential for an influx of birds breeding elsewhere.

Figure 11.1:
Offshore Ornithology Study Areas

Figure 11.1: Offshore Ornithology Study Areas


11.4. Policy and Legislative Context

  1. Volume 1, chapter 2 of the Array EIA Report presents the policy and legislation of relevance to renewable energy infrastructure. Policy specifically in relation to offshore ornithology is contained in the Sectoral Marine Plan (SMP) for Offshore Wind Energy (Scottish Government, 2020), the Scottish National Marine Plan (NMP) (Scottish Government, 2015) and the United Kingdom (UK) Marine Policy Statement (MPS) (HM Government, 2011). Table 11.1   Open ▸ presents a summary of the legislative provisions relevant to offshore ornithology, with relevant policy provisions set out in Table 11.2   Open ▸ and Table 11.3   Open ▸ . Further detail is presented in volume 1, chapter 2.

 

Table 11.1:
Summary of Legislation Relevant to Offshore Ornithology

Table 11.1: Summary of Legislation Relevant to Offshore Ornithology

Table 11.2:
Summary of Policy Provisions Relevant to Offshore Ornithology

Table 11.2: Summary of Policy Provisions Relevant to Offshore Ornithology