In-combination: Conclusion
  1. On the basis of the Developer Approach, the potential effects from the Proposed Development in-combination with other UK North Sea wind farms on the North Caithness Cliffs SPA kittiwake population are predicted to be relatively moderate. Although the impact on the population growth rate is small. The PVA metrics indicate that it is possible that the population would be smaller to that which would occur in the absence of the in-combination impacts. For the Scoping Approach, the predicted reductions in population size and the likelihood of them occurring size are greater.
  2. It is considered likely that the assessment is overly precautionary and the level of impact would be lower than predicted. However, the population is in unfavourable condition and declining and it is therefore considered to be the potential for an adverse effect on the North Caithness Cliffs SPA kittiwake population as a result of the predicted in-combination effects. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approaches.

Assessment for the puffin population

  1. The North Caithness Cliffs SPA puffin population is currently estimated to number 1,517 breeding pairs (Offshore EIA Report, volume 3, appendix 11.5) based on the most recent count in 2015/16. Puffin are listed on the North Caithness Cliffs SPA citation as a named component of the breeding seabird assemblage, with a citation population size of 2,080 pairs, thus the numbers currently breeding on North Caithness Cliffs show an apparent decline in the population since designation. Although the population is considered to be in favourable and maintained condition.
  2. Potential impacts on the North Caithness Cliffs SPA puffin population screened in for assessment are outlined in section 3 and in the HRA Stage One Screening Report (SSER, 2021b).
The potential for impacts on the puffin population
  1. The breeding period for puffin is defined as April to mid-August, following the NatureScot (2020) guidance. From published information on puffin foraging ranges generally (Woodward et al. 2019) it is possible that during the breeding period puffin from North Caithness Cliffs SPA occur within the Proposed Development and 2 km buffer. However, the number of puffins present are predicted to be very low with the results of the apportioning exercise estimating that 0.2% of the puffin occurring on the Proposed Development array area during the breeding season derive from this SPA colony (Offshore EIA Report, volume 3, appendix 11.5).
  2. As advised in the NatureScot scoping advice (volume 3, appendix 6.2 of the Offshore EIA Report), no assessment of impacts during the non-breeding period is undertaken for puffin.
Project alone: construction and decommissioning
Disturbance
  1. As outlined in the section on Project Alone: Construction and Decommissioning – Disturbance for the Forth Island SPA puffin population, direct disturbance to puffins during the (at most) eight-year construction phase may arise within the Proposed Development as a result of increased vessel movements, as well as from other activities associated with the installation of the wind turbine foundations, cables and other infrastructure (see maximum design scenario, Table 4.1   Open ▸ ).
  2. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
  3. Given the relatively low sensitivity of puffin to disturbance effects (Garthe and Hüppop 2004; Furness et al., 2013), the relatively small areas that will be subject to activities with the potential to result in disturbance at any given time during the construction period and the fact that these potential effects will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Displacement
  1. As detailed above, puffin is considered to have a low sensitivity to disturbance (Garthe and Hüppop 2004; Furness et al., 2013), and potential effects of disturbance during the construction and decommissioning phases will only extend across a very small part of the wider foraging areas used by the North Caithness Cliffs SPA puffin population during the breeding season. Furthermore, as detailed in section above, potential effects of disturbance will not occur simultaneously across the entirety of the Proposed Development array area and Proposed Development export cable corridor but will instead be carried out in different areas at different times. Thus, at any given time the potential for disturbance effects that could lead to displacement of puffin from this SPA during the breeding period will be limited to relatively small areas, with the potential effects also being of a temporary nature.
  2. Therefore, it is considered that there is no potential for construction or decommissioning related displacement to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Changes to prey availability
  1. During construction and decommissioning there are a number of ways in which effects on key prey species of seabirds may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the Forth Islands SPA puffin population. The same evidence basis and context applies to the North Caithness Cliffs SPA puffin population as to the Forth Islands SPA population in relation to the potential for such effects to lead to impacts on the population.
  2. Given this, it is considered that there is relatively little potential for the North Caithness Cliffs SPA puffin population to be affected by changes to prey availability during the construction and decommissioning phases, with any such effects being largely intermittent across a relatively small spatial extent, with most effects temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Project alone: operation and maintenance
Disturbance
  1. Vessel use and associated activities within the Proposed Development array area and export cable corridor during the operation and maintenance phase may lead to direct disturbance of puffins from North Caithness Cliffs SPA during the breeding periods, as outlined in the section on Project Alone: Operation and Maintenance – Disturbance for the Forth Islands SPA puffin population. The same evidence base and context applies to the North Caithness Cliffs SPA puffin population as to the Forth Islands SPA population in relation to the potential for such effects to lead to impacts on the population during the non-breeding periods.
  2. Given the discrete areas relative to the species’ breeding season foraging range that will be subject intermittently to potential disturbance from vessel use and maintenance activities, and the fact that these potential effects will be reduced compared to the construction and decommissioning phases, it is considered that there is no potential for disturbance during operation and maintenance to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Displacement/Barrier effects
  1. The approach used to derive predicted levels of mortality for North Caithness Cliffs SPA puffins is as described in the section on Project Alone: Operation and Maintenance – Displacement/Barrier effects for the Forth Islands SPA puffin population (and in the Offshore EIA Report, volume 3, appendix 11.4)
  2. Estimates of puffin mortality for North Caithness Cliffs SPA were produced using the SNCB matrix on the basis of both the Scoping Approaches and the Developer Approach (Offshore EIA Report, volume 3, appendix 11.4), with these estimates then apportioned to the North Caithness Cliffs SPA puffin population as described in volume 3, appendix 11.5 of the Offshore EIA Report and in the section on Project Alone: Operation and Maintenance – Displacement/Barrier effects for the Forth Islands SPA puffin population (and according to the apportioning estimates in Table 5.218).

 

Table 5.218:
The Mean Peak Abundance Estimates of Puffin in the Proposed Development Array Area and 2 km Buffer for Each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be From the North Caithness Cliffs SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented.

Table 5.218: The Mean Peak Abundance Estimates of Puffin in the Proposed Development Array Area and 2 km Buffer for Each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be From the North Caithness Cliffs SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented.

 

Table 5.219:
Estimated Potential Annual Mortality of North Caithness Cliffs SPA Puffins as a Result of Displacement From the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach.

Table 5.219: Estimated Potential Annual Mortality of North Caithness Cliffs SPA Puffins as a Result of Displacement From the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach.

 

  1. The potential annual mortality as a result of displacement is estimated as between 0 and 0.1 adults and 0 and 0.1 immatures based on Developer and Scoping Approaches ( Table 5.219   Open ▸ ).
  2. The additional annual mortality of adult puffins from the North Caithness Cliffs SPA population predicted under Scoping Approach B due to displacement from the Proposed Development array area represents 0.003% of the current adult breeding population at this colony (i.e. 3,034 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report). Under all other approaches no adult mortality is predicted.
  3. Further consideration of the potential population-level impacts associated with the predicted displacement/barrier effect mortalities in Table 5.219   Open ▸ is undertaken below in the Project Alone: population-level impacts section.
Changes to prey availability
  1. During the operation and maintenance phase there are a number of ways in which effects on key prey species may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the Forth Islands SPA puffin population. The same evidence base and context applies to the North Caithness Cliffs SPA puffin population as to the Forth Islands SPA population in relation to the potential for such effects to lead to impacts on the population.
  2. Given this, it is considered that there is relatively little potential for the North Caithness Cliffs SPA puffin population to be affected by changes to prey availability during the operation and maintenance phase, with any such effects being largely intermittent across a relatively small spatial extent. Consequently, it is considered that there is no potential for operation or maintenance related changes in prey availability to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Project alone: population-level impacts
  1. As determined above, the effects from the Proposed Development alone which could lead to an adverse effect on the Forth Islands SPA puffin population are limited to displacement (inclusive of barrier effects) during the operation and maintenance phase. For other effect pathways, there is considered to be no potential for an adverse effect on this population as a result of the Proposed Development alone, with any such effects likely to be small and of little, or no, consequence in terms of impacts at the population level.
  2. As described in the Offshore EIA Report, volume 3, appendix 11.6, PVAs were run for populations where the predicted wind farm associated mortality increased the baseline mortality rate by at least 0.02 percentage point (Offshore EIA Report, volume 3, appendix 11.8). Predicted displacement mortality for the North Caithness Cliffs SPA puffin population did not exceed this threshold under any approach and as such, PVA was not undertaken. Accordingly, it is considered that there is no potential for operation or maintenance related displacement/barrier effects to lead to an adverse effect on the North Caithness Cliffs SPA puffin population.
Project alone: Conclusion
  1. For both the Developer and Scoping Approaches, the potential effects from the Proposed Development alone on the North Caithness Cliffs SPA puffin population are predicted to be very small, with the resultant population-level impacts also predicted to be very small. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this SPA population.
Effects in-combination
Effects of relevance to the in-combination assessment
  1. For the same reason as described in Effects in-combination for the Forth Islands SPA puffin population, the potential for effects of the Proposed Development to act on the North Caithness Cliffs SPA puffin population in-combination with other plans and projects is limited to displacement (inclusive of barrier effects) during operation and maintenance. For the North Caithness Cliffs SPA puffin population, potential effects of displacement are limited to the breeding season.

 

Displacement/Barrier effects – operation and maintenance
  1. Existing assessments for all UK North Sea offshore wind farms that are in operation, construction, consented or planning were checked to determine the displacement mortality estimates to be attributed to the North Caithness Cliffs SPA puffin population (Offshore EIA Report, volume 3, appendix 11.6, annex E).
  2. Following the approach to estimating in-combination mortalities as outlined in volume 3, appendix 11.6, annex E of the Offshore EIA Report, there are no projects considered to have effects on the North Caithness Cliffs SPA puffin population during the breeding season. Therefore, it is assumed that existing in-combination effects are inconsequential to this feature and that, in line with conclusions for the project alone, in-combination population-level impacts resulting from predicted collision mortality are negligible.
In-combination: Conclusion
  1. On the basis of the above considerations, it is concluded that the population-level impacts resulting from the Proposed Development in-combination with the other UK North Sea wind farms would not produce an adverse effect on the North Caithness Cliffs SPA puffin population. This conclusion applies irrespective of whether effects are determined according to the Scoping Approach or the Developer Approach.

Assessment for the breeding seabird assemblage

  1. The breeding seabird assemblage for the North Caithness Cliffs SPA is a qualifying feature on the basis of the SPA supporting in excess of 20,000 individual seabirds (with the citation noting a total of 110,000 individual breeding seabirds). Fulmar, kittiwake, guillemot, razorbill and puffin are amongst the species identified in the citation as having nationally important populations which contribute to the North Caithness Cliffs SPA breeding seabird assemblage.
  2. Potential impacts of the Proposed Development alone and in-combination with other UK North Sea wind farms on the breeding seabird assemblage for the SPA could arise via effects on the named components of the assemblage feature. For both the Scoping Approach and the Developer Approach, the assessments undertaken above identify no potential for adverse effects on kittiwake or puffin for the project alone or for puffin for the project in-combination with other plans or projects.  Likely significant effects on all other named components of the assemblage have been screened out (Table 5.210). 
  3. The assessment identifies the potential for an adverse effect to arise from the Proposed Development in-combination with other plans or projects on kittiwake.
  4. Therefore, it is concluded that there is potential for an adverse effect on the North Caithness Cliffs breeding seabird assemblage. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.

Site conclusion

  1. It is concluded that there is no potential for an Adverse Effect on Integrity on the North Caithness Cliffs SPA from the Proposed Development alone. There is potential for an Adverse Effect on Integrity from the Proposed Development in-combination with other UK North Sea wind farms.  This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.

5.7.11.              Hoy SPA

European site information and conservation objectives

  1. Hoy is a mountainous island at the south-western end of the Orkney archipelago, located approximately 312 km from the Proposed Development. Hoy SPA covers the northern and western two-thirds of Hoy island. The boundary of Hoy SPA overlaps with that of Hoy SSSI, and the seaward extension extends approximately 2 km into the marine environment. The SPA was classified in 2000, with the marine extension classified in 2009.
  2. There is one annex 1 qualifying seabird species and the site qualifies under Article 4.2 by regularly supporting one migratory seabird species and in excess of 20,000 breeding seabirds, including six named component species ( Table 5.220   Open ▸ ). The potential for LSE has been identified in relation to three species: kittiwake, great skua and puffin along with the Seabird Assemblage ( Table 5.220   Open ▸ ), with the effect pathways associated with LSE for each of these detailed in Table 3.1   Open ▸ and set out in the assessment below.
  3. The conservation objectives of this SPA (as determined from NatureScot’s SiteLink (NatureScot 2022) are:
  • To avoid deterioration of the habitats of the qualifying species (listed below) or significant disturbance to the qualifying species, thus ensuring that the integrity of the site is maintained; and
  • To ensure for the qualifying species that the following are maintained in the long term:

–           Population of the species as a viable component of the site

–           Distribution of the species within site

–           Distribution and extent of habitats supporting the species

–           Structure, function and supporting processes of habitats supporting the species

–           No significant disturbance of the species

  1. The Proposed Development does not overlap with the SPA, so that potential impacts on its qualifying features will only occur as a result of individuals from the colony occurring in the area (or vicinity) of the Proposed Development.
  2. Consequently, the focus of the assessment for this SPA population is concerned with the conservation objective to maintain or restore the populations of each qualifying feature because the other conservation objectives either apply to the site itself, and not to areas beyond the boundary, or are encompassed by the assessment of this conservation objective.
  3. Further information on this European site is presented in appendix 3A.

 

Table 5.220:
Details on the Qualifying Features of Hoy SPA

Table 5.220: Details on the Qualifying Features of Hoy SPA

*Named components of the assemblage only.

Assessment for the kittiwake population

  1. The Hoy SPA kittiwake population is currently estimated to number 608 breeding pairs (Offshore EIA Report, volume 3, appendix 11.5) based on the most recent count in 2016/17. Kittiwake are listed on the Hoy SPA citation as a named component of the breeding seabird assemblage.
  2. Potential impacts on the Hoy SPA kittiwake population screened in for assessment are outlined in section 3 and in the HRA Stage One Screening Report (SSER, 2021b).
The potential for impacts on the kittiwake population
  1. The breeding period for kittiwake is defined as mid-April to August, following the NatureScot (2020) guidance. From published information on kittiwake foraging ranges generally (Woodward et al., 2019) it is apparent that during the breeding period kittiwakes from Hoy SPA could occur in the vicinity of the Proposed Development. However, the findings of the apportioning exercise found that no kittiwakes occurring in the Proposed Development array area during the breeding season derived from this SPA (Offshore EIA Report, volume 3, appendix 11.5: Table 4.5).
  2. In the non-breeding season kittiwakes are largely pelagic (Frederiksen et al., 2011), although most of those which breed on the North Sea coast likely winter in the North Sea and Celtic Sea. Therefore, it is likely that there is the potential for birds from the Hoy SPA population to pass through offshore wind farms in the North Sea during the autumn and spring passage periods (defined as September to December and January to mid-April, respectively - Furness 2015; NatureScot 2020; Offshore EIA Report, volume 3, appendix 11.5). Given the above, the Proposed Development may have potential effects on the Hoy SPA kittiwake population during the non-breeding passage periods only (Offshore EIA Report, volume 3, appendix 11.5).
Project alone: construction and decommissioning
Disturbance
  1. Direct disturbance to kittiwakes during the construction phase may arise within the Proposed Development as a result of increased vessel movements, as well as from other activities associated with the installation of the wind turbine foundations, cables and other infrastructure (see the section on Project Alone: Construction and Decommissioning – Disturbance for St. Abb’s Head to Fast Castle kittiwake population, Table 5.4   Open ▸ ).
  2. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
  3. Kittiwakes breeding at the Hoy SPA are not predicted to utilise the Proposed Development during the breeding season (Offshore EIA Report, volume 3, appendix 11.5). During the non-breeding periods, kittiwake distribution is not constrained by the location of the breeding colonies and birds from the SPA population are likely to occur across large expanses of oceanic and maritime waters (Frederiksen et al., 2012, Furness 2015). The potential for effects of construction- and decommissioning-related disturbance is therefore low.
  4. Furthermore, given the low sensitivity of kittiwake to disturbance effects (Garthe and Hüppop 2004; Furness et al., 2013), and the relatively small areas that will be subject to activities with the potential to result in intermittent, temporary disturbance (see the section on Project Alone: Construction and Decommissioning – Disturbance for St. Abb’s Head to Fast Castle kittiwake population), it is considered that there is no potential for construction or decommissioning related disturbance to lead to an adverse effect on the Hoy SPA kittiwake population. This conclusion is consistent with the outcome of the EIA which ‘screened’ out kittiwake as a species for which detailed consideration of the effects of construction disturbance was required (Chapter 11, Offshore EIA Report).
Displacement
  1. As detailed above, kittiwake is considered to have a low sensitivity to disturbance (Garthe and Hüppop 2004; Furness et al., 2013), and potential effects of disturbance during the construction and decommissioning phases will only extend across a very small part of the wider foraging areas used by the Hoy SPA kittiwake population during the non-breeding season. Furthermore, as detailed in the section on Project Alone: Construction and Decommissioning – Displacement for St. Abb’s Head to Fast Castle kittiwake population, potential effects of disturbance will not occur simultaneously across the entirety of the Proposed Development array area and Proposed Development export cable corridor but will instead be carried out in different areas at different times. Thus, at any given time the potential for disturbance effects that could lead to displacement of kittiwake from this SPA during the non-breeding periods will be limited to relatively small areas, with the potential effects also being of a temporary nature.
  2. Therefore, it is considered that there is no potential for construction or decommissioning related displacement to lead to an adverse effect on the Hoy SPA kittiwake population.
Changes to prey availability
  1. During construction and decommissioning there are a number of ways in which effects on key prey species of seabirds may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the St Abb’s Head to Fast Castle SPA kittiwake population. The same evidence basis and context applies to the Hoy SPA kittiwake population as to the St Abb’s Head to Fast Castle SPA population in relation to the potential for such effects to lead to impacts on the population.
  2. Given this, it is considered that there is no potential for the Hoy SPA kittiwake population to be affected by changes to prey availability during the construction and decommissioning phases, with any such effects being largely intermittent across a relatively small spatial extent, with most effects temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Hoy SPA kittiwake population.
Project alone: operation and maintenance
Disturbance
  1. Vessel use and associated activities within the Proposed Development array area and export cable corridor during the operation and maintenance phase may lead to direct disturbance of kittiwakes from Hoy SPA during the non-breeding periods, as outlined in the section on Project Alone: Operation and Maintenance – Disturbance for the St. Abb’s Head to Fast Castle SPA kittiwake population. The same evidence base and context applies to the Hoy SPA kittiwake population as to the St Abb’s Head to Fast Castle SPA population in relation to the potential for such effects to lead to impacts on the population during the non-breeding periods.
  2. Given the discrete areas relative to the species’ non-breeding season foraging range that will be subject intermittently to potential disturbance from vessel use and maintenance activities, and the fact that these potential effects will be reduced compared to the construction and decommissioning phases, it is considered that there is no potential for disturbance during operation and maintenance to lead to an adverse effect on the Hoy SPA kittiwake population.
Displacement/Barrier effects
  1. The approach used to derive predicted levels of mortality for Hoy SPA kittiwakes is as described in the section on Project Alone: Operation and Maintenance – Displacement/Barrier effects for the St Abb’s Head to Fast Castle SPA kittiwake population (and in volume 3, appendix 11.4 of the Offshore EIA Report)
  2. Estimates of kittiwake mortality for Hoy SPA were produced using the SNCB matrix on the basis of both the Scoping Approaches and the Developer Approach (Offshore EIA Report, volume 3, appendix 11.4), with these estimates then apportioned to the Hoy SPA kittiwake population as described in volume 3, appendix 11.5 of the Offshore EIA Report and in the section on Project Alone: Operation and Maintenance – Displacement/Barrier effects for the St Abb’s Head to Fast Castle SPA kittiwake population (and according to the apportioning estimates in Table 5.211).

 

Table 5.221:
The Mean Peak Abundance Estimates of Kittiwake in the Proposed Development Array Area and 2 km Buffer for each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be From the Hoy SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented

Table 5.221: The Mean Peak Abundance Estimates of Kittiwake in the Proposed Development Array Area and 2 km Buffer for each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be From the Hoy SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented

 

Table 5.222:
Estimated Potential Annual Mortality of Hoy SPA Kittiwakes as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach

Table 5.222: Estimated Potential Annual Mortality of Hoy SPA Kittiwakes as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach

 

  1. The potential annual mortality as a result of displacement is estimated as 0.1 adult and no immature birds based on Scoping Approach A and as 0.2 adult and no immature birds based Scoping Approach B (Table 5.222). All mortality was attributable to the non-breeding periods.
  2. No mortality from displacement was predicted using the Developer Approach for any age class or season Table 5.222).
  3. The additional annual mortality of adult kittiwakes from the Hoy SPA population predicted due to displacement from the Proposed Development array area represents 0.016% of the current adult breeding population at this colony (i.e. 608 individuals – Table 4.5 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by Scoping Approach A, and 0.03% as determined by Scoping Approach B. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.188 from West Westray, the closest colony to Hoy– see Table 2.13 of volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult mortality equate to an increase of 0.09 – 0.17% for the lower and upper estimates from the Scoping Approach. As outlined above and in Table 5.222   Open ▸ , no mortality was predicted using the Developer Approach.
Collision risk
  1. The approach used to derive predicted levels of mortality for Hoy SPA kittiwakes is as described in the section on Project Alone: Operation and Maintenance – Collision risk for the St Abb’s Head to Fast Castle SPA kittiwake population (and in the Offshore EIA Report, volume 3, appendix 11.3)
  2. Based upon option 2 of the deterministic CRM with a 98.9% avoidance rate applied, the annual collision mortality of kittiwakes from the Hoy SPA is predicted to be approximately 0.4 adults and no immatures as determined by the Scoping Approach, and approximately 0.3 adults and no immatures as determined by the Developer Approach ( Table 5.223   Open ▸ ). All mortality was attributable to the non-breeding periods.

 

Table 5.223:
Predicted Collision Effects from the Proposed Development on the Hoy SPA Kittiwake Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98.9% Avoidance Rate

Table 5.223: Predicted Collision Effects from the Proposed Development on the Hoy SPA Kittiwake Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98.9% Avoidance Rate

 

  1. The additional annual mortality of adult kittiwakes from the Hoy SPA population predicted due to collision represents approximately 0.05% of the number of adults currently estimated to breed at this colony (i.e. 608 individuals – Table 4.5 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach and approximately 0.06% as determined by the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying the West Westray mortality rate of 0.188 – see Table 2.13 of volume 3, appendix 11.6 of the Offshore EIA Report), the predicted adult collision mortality equates to increases of 0.26% and 0.35% for the Developer and Scoping Approaches, respectively.
  2. As outlined in the Project Alone: Operation and Maintenance - Collision risk section for the St Abb’s Head to Fast Castle SPA kittiwake population, using the collision estimates derived from the site-specific flight height data or from the stochastic CRM with avoidance rates as calculated for the bird collision-avoidance study (Bowgen and Cook 2018) would result in predicted collision mortalities on the Hoy SPA kittiwake population that are at least 50% lower than those presented in Table 5.223   Open ▸ above (and on which the assessment is based).
Changes to prey availability
  1. During the operation and maintenance phase there are a number of ways in which effects on key prey species may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the St Abb’s Head to Fast Castle SPA kittiwake population. The same evidence base and context applies to the Hoy SPA kittiwake population as to the St Abb’s Head to Fast Castle SPA population in relation to the potential for such effects to lead to impacts on the population.
  2. Given this, it is considered that there is no potential for the Hoy SPA kittiwake population to be affected by changes to prey availability during the operation and maintenance phase, with any such effects being largely intermittent across a relatively small spatial extent. Consequently, it is considered that there is no potential for operation or maintenance related changes in prey availability to lead to an adverse effect on the Hoy SPA kittiwake population.
Project alone: population-level impacts
  1. As determined above, the effects from the Proposed Development alone which could lead to an adverse effect on the Hoy SPA kittiwake population are displacement (inclusive of barrier effects) and collision mortality during the operation and maintenance phase.
  2. The predicted population-level impacts are small, irrespective of whether these are determined using the Developer or Scoping Approaches.  The potential increase in annual adult mortality from displacement is between zero and 0.2 birds per year and those from collision impacts from between 0.3 and 0.4 adult birds per year.
Project alone: Conclusion
  1. For both the Developer and Scoping Approaches, the potential effects from the Proposed Development alone on the Hoy SPA kittiwake population are predicted to be small, with the resultant population-level impacts also predicted to be small. Any impacts are likely to be within the natural variation of the population. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this SPA population.
Effects in-combination
Effects of relevance to the in-combination assessment
  1. For the same reasons as described in Effects in-combination for the St. Abb’s Head to Fast Castle SPA kittiwake population, the potential for effects of the Proposed Development to act on the Hoy SPA kittiwake population in-combination with other plans and projects is limited to displacement/barrier effect and collision risk pathways during operation and maintenance.
  2. In-combination totals have been collated for all relevant SPA populations for all UK North Sea and Channel offshore wind farms in operation, construction, consented or planning (Offshore EIA Report, volume 3, appendix 11.6, annex E). Separate in-combination totals for the Forth and Tay projects were not collated for the reasons outlined in Effects in-combination for the Farne Islands SPA kittiwake population, volume 3, appendix 11.6, annex E and volume 3, appendix 11.8 of the Offshore EIA Report.
Displacement/Barrier effects – operation and maintenance
  1. The approach and methods for estimating in-combination displacement mortality are described in Effects in-combination: Displacement/Barrier Effects – Operation and Maintenance for St Abb’s Head to Fast Castle SPA kittiwake population above and in volume 3, appendix 11.6, annex E of the Offshore EIA Report.
  2. The potential mortality estimates derived for the other projects were combined with those for the Proposed Development to give in-combination estimates for the UK North Sea wind farm scenario, according to both the Scoping Approaches and Developer Approach ( Table 5.224   Open ▸ ).

 

Table 5.224:
Estimated Annual Mortality of Hoy SPA Kittiwakes as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, in-Combination With Other UK North Sea Wind Farms

Table 5.224: Estimated Annual Mortality of Hoy SPA Kittiwakes as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, in-Combination With Other UK North Sea Wind Farms

 

  1. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult kittiwakes from the Hoy SPA population predicted due to displacement represents between approximately 0.05-0.14% of the current adult breeding population at this colony (i.e. 608 individuals – Table 4.5 in volume 3, appendix 11.5 of the Offshore EIA Report), as determined by Scoping Approach A and B. In terms of percentage increases in the baseline annual adult mortality of the population, the estimates of adult displacement mortality equate to an increase of 0.26 – 0.79% for the lower and upper estimates from the Scoping Approach. No mortality of kittiwake from displacement effects is predicted to occur following the Developer Approach.
Collision risk - operation and maintenance
  1. The approach and methods for estimating in-combination collision mortality are described in Effects in-combination: Collision – Operation and Maintenance for St Abb’s Head to Fast Castle SPA kittiwake population above and in volume 3, appendix 11.6, annex E of the Offshore EIA Report.
  2. The potential mortality estimates derived for the other projects were combined with those for the Proposed Development to give in-combination estimates for the UK North Sea wind farm scenario, according to both the Scoping Approach and Developer Approach ( Table 5.225   Open ▸ ).

 

Table 5.225:
Predicted Collision Effects on the Hoy SPA Kittiwake Population Due to the Proposed Development in-Combination With Other Projects in the UK North Sea waters. Estimates are Presented for Both the Scoping Approach and Developer Approach for Consented Designs

Table 5.225: Predicted Collision Effects on the Hoy SPA Kittiwake Population Due to the Proposed Development in-Combination With Other Projects in the UK North Sea waters. Estimates are Presented for Both the Scoping Approach and Developer Approach for Consented Designs

 

  1. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult kittiwakes from the Hoy SPA population predicted due to collisions represents 0.23% of the current adult breeding population at this colony (i.e. 608 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, and 0.25% of this population as determined by the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population, the estimates of adult collision mortality equate to an increase of 1.22% for the Developer Approach and of 1.32% for the Scoping Approach.
In-combination: population-level impacts
  1. The combined in-combination impacts arising from both displacement and collision impacts are presented in Table 5.226   Open ▸ .

 

Table 5.226:
Predicted Collision Effects on the Hoy SPA Kittiwake Population Due to the Proposed Development in-Combination With Other Projects in the UK North Sea waters. Estimates are Presented for Both the Scoping Approach and Developer Approach for Consented Designs

Table 5.226: Predicted Collision Effects on the Hoy SPA Kittiwake Population Due to the Proposed Development in-Combination With Other Projects in the UK North Sea waters. Estimates are Presented for Both the Scoping Approach and Developer Approach for Consented Designs

 

  1. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult kittiwakes from the Hoy SPA population predicted due to the combined impacts from displacement and collisions represents 0.23% of the current adult breeding population at this colony (i.e. 608 individuals – Table 4.5 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, 0.29% of this population as determined by the Scoping Approach A and 0.39% for Scoping Approach B. In terms of percentage increases in the baseline annual adult mortality of the population, the estimates of adult mortality equate to an increase of 1.6% for the Developer Approach and of 0.75% for the Scoping Approach B and up to 2.0% based on Scoping Approach B.
  2. The predicted in-combination population-level impacts are small, in particular if the Developer Approach are considered. Although it is recognised that the kittiwake population is declining and identified as being in unfavourable condition, any in-combination impacts are likely to be within the natural variation of the population. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this SPA population.
In-combination: Conclusion
  1. Based on the Developer and Scoping Approaches, the potential effects from the Proposed Development in-combination with other UK North Sea wind farms on the Hoy SPA kittiwake population are predicted to be small, with the resultant population-level impacts also predicted to be relatively small. Considering this within the context of a highly precautionary assessment, it is concluded that the in-combination scenario for both the Scoping and Developer Approaches would not result in adverse effect on the Hoy SPA kittiwake population.

Assessment for the great skua population

  1. Great skua only occur in the North Atlantic, nesting at relatively high latitudes and wintering south of their breeding sites. Most great skua nest in the eastern Atlantic, with an estimated global breeding population of 16,000 pairs, of which approximately 60% nest on islands in north and west Scotland. Great skua also nests in Faroes, Norway and Iceland and a small population breed in Ireland. Great skua forage on fish obtained via Kleptoparasitism from other seabird species and discards from fishing boats. They also predate on other seabird species. Great skua have a large foraging range when breeding, with the mean maximum foraging range reported as being 443.3 km (±487.9) (Woodward et al. 2019).
  2. The Hoy SPA great skua population is currently estimated to number 1,041 Apparently Occupied Territories (2,082 individuals) based on the most recent count in 2019.
The potential for impacts on the great skua population
  1. Potential impacts on the Hoy SPA great skua population screened in for assessment are outlined in the HRA Stage One Screening Report (SSER, 2021b).
  2. From published information on great skua foraging ranges it is apparent that during the breeding period great skua from the Hoy SPA could, in theory, occur within the area of the Proposed Development and the 2 km buffer around the Proposed Development Array area (Woodward et al. 2019). The breeding period for great skua is defined as mid-April to mid-September, following the NatureScot (2020) guidance
  3. Great skuas move south in autumn to winter at sea from the Bay of Biscay to the seas off west Africa and also North America returning north in the spring (Furness 2015), so that the non-breeding season is divided into autumn and spring passage periods (defined as August to October and March to April, respectively, with the winter period from November to February). Given the above, the Proposed Development may have potential effects on the Hoy SPA great skua population during breeding and non-breeding periods.
Project alone: operation and maintenance
Collision risk
  1. Predictions of the number of great skua at risk from collisions due to the Proposed Development were calculated using the deterministic version of the SOSS offshore collision risk model (Band 2012, Offshore EIA Report appendix 11.3 in Table 4.9). The assessment is based on the outputs from both options 2 and 3 of the CRM, which use the generic flight height data and for which option 2 assumes a uniform distribution of flight heights across the rotor swept zone and option 3 assumes the modelled flight height distribution (Band 2012, Johnston et al. 2014a,b). In accordance with the recommendations of the SNCBs (2014) avoidance rates of 98.0% were applied to the outputs from option 2 and option 3, respectively. Annual great skua collision estimates are calculated.
  2. As outlined elsewhere (e.g. the St Abb’s Head to Fast Castle SPA kittiwake CRM) the CRMs for great skua were undertaken following:
  • The Scoping Approach of using the maximum monthly densities, and
  • The Developer Approach of using the mean monthly densities.
  1. Based upon the Developer Approach option 2 of the deterministic CRM with a 98.0% avoidance rate applied, the total annual collision mortality of great skua is 0.18 adults. Based on the Scoping Approach option 2 and a 98% avoidance rate the total annual mortality of great skua is estimated to be 0.35 ( Table 5.227   Open ▸ and see appendix 11.3 Table 4.9) for all modelled scenarios). The estimated impacts based on the use of option 3 were lower at 0.02 and 0.05 birds per year for Developer and Scoping Approaches respectively.

 

Table 5.227:
Predicted Collision Effects From the Proposed Development on Great Skua Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98% Avoidance Rate

Table 5.227: Predicted Collision Effects From the Proposed Development on Great Skua Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98% Avoidance Rate

 

  1. Based upon the estimates from option 2 of the CRM, the additional annual mortality of great skua is 0.18 birds per year based on the Developer Approach.  Under a worst-case scenario all 0.18 collisions per year have been assumed to be adults and apportioned to the Hoy SPA breeding population. On this highly precautionary and unrealistic worst-case scenario it is estimated that the predicted collisions represent approximately 0.008% of the number of adults currently estimated to breed at this colony (i.e. 1,041 individuals) as determined by the Developer Approach and approximately 0.016% as determined by the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.112 – Robinson 2022), the predicted adult collision mortality equates to increases of 0.08% and 0.15% for the Developer and Scoping Approaches, respectively.
  2. The estimated number of collisions per annum relates to impacts on the whole great skua population and not just adults from this SPA. Most impacts are predicted to occur during spring and autumn passage periods (appendix 11.1: section 5.14) when approximately 14.1% of the North Sea great skua population are birds from Hoy SPA (Furness 2015). Consequently, of the 0.18 collisions per year 14.1% could be predicted to be on birds from this SPA, equating to collision mortality of 0.02 birds per year based on the Developers Approach and 0.05 birds per year based on Scoping Approach. This estimated number of collisions represent approximately <0.001% of the number of adults currently estimated to breed at this colony (i.e. 1,041 individuals) as determined by the Developer Approach and approximately 0.002% as determined by the Scoping Approach.  In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.112 – Robinson 2022), the predicted adult collision mortality equates to increases of 0.009% and 0.021% for the Developer and Scoping Approaches, respectively.
Project alone: Conclusion
  1. For both the Developer and Scoping Approaches, the potential effects from the Proposed Development alone on the Hoy SPA great skua population are predicted to be negligible, with the resultant population-level impacts also predicted to be negligible. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.
Effects in-combination
Collision risk

As detailed above, any effects from the Proposed Development alone on the Hoy SPA great skua population resulting from collision during operation and maintenance will be very small impacting on no more than 0.002% of the adult population and increasing the adult mortality by no more than 0.021%. Consequently, it is considered that there is no potential for an effect from the Proposed Development to add to impacts at a population level that could cause an in-combination adverse effect.

In-combination: Conclusion
  1. On the basis of the above considerations, it is concluded that the population-level impacts resulting from the Proposed Development in-combination with the other UK North Sea wind farms would not produce an adverse effect on the Hoy SPA great skua population. This conclusion applies irrespective of whether effects are determined according to the Scoping Approach or the Developer Approach.

Assessment for the puffin population

  1. The Hoy SPA puffin population is currently estimated to number 361 individuals.
  2. Potential impacts on the Hoy SPA puffin population screened in for assessment are outlined in section 3 and in the HRA Stage One Screening Report (SSER, 2021b).
The potential for impacts on the puffin population
  1. The breeding period for puffin is defined as April to mid-August, following the NatureScot (2020) guidance. From published information on puffin foraging ranges generally (Woodward et al. 2019) it is possible that during the breeding period puffin from Hoy SPA occur within the Proposed Development and 2 km buffer. However, the SPA is 312 km from the Proposed Development and the results from the apportioning exercise indicate that no puffins occurring in the Proposed Development array area during the breeding season are from this SPA colony (Offshore EIA Report, volume 3, appendix 11.5).
  2. As advised in the NatureScot scoping advice (volume 3, appendix 6.2 of the Offshore EIA Report), no assessment of impacts during the non-breeding period is undertaken for puffin.
Project alone: construction and decommissioning
Disturbance
  1. As outlined in the section on Project Alone: Construction and Decommissioning – Disturbance for the Forth Island SPA puffin population, direct disturbance to puffins during the assumed eight-year construction phase may arise within the Proposed Development as a result of increased vessel movements, as well as from other activities associated with the installation of the wind turbine foundations, cables and other infrastructure (see maximum design scenario; Table 4.1   Open ▸ ).
  2. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
  3. Given the relatively low sensitivity of puffin to disturbance effects (Garthe and Hüppop 2004; Furness et al., 2013), the relatively small areas that will be subject to activities with the potential to result in disturbance at any given time during the construction period and the fact that these potential effects will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance to lead to an adverse effect on the Hoy SPA puffin population.