Tier 1 and Tier 2

                        Kittiwake
  1. The estimated collision mortalities of kittiwake for the purpose of estimating cumulative collisions impacts are given in Table 11.71   Open ▸ . Estimated collisions for projects are those presented by Berwick Bank (SSE Renewables, 2022), for which NatureScot has not raised any concerns or noted any errors. In addition, estimates have been obtained from Green Volt Offshore Wind Farm (Green Volt, 2023), Pentland Floating Offshore Wind (Pentland Floating Offshore Wind Farm, 2022), West of Orkney (Offshore Wind Power Limited, 2023), North Falls (North Falls, 2023), Five Estuaries (Five Estuaries, 2023) and Outer Dowsing (Outer Dowsing, 2023) offshore wind farms, as those projects had not published their estimates at the time of the Berwick Bank application.

 

Table 11.71:
Kittiwake Cumulative Collision Mortalities

Table 11.71: Kittiwake Cumulative Collision Mortalities

 

  1. The cumulative collision mortality is given in Table 11.72   Open ▸ (with Berwick Bank included) and Table 11.73   Open ▸ (with Berwick Bank excluded).

 

Table 11.72:
Kittiwake Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

Table 11.72: Kittiwake Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

 

  1. With Berwick Bank, the estimated collision mortality for kittiwake is 1,021 individuals in the pre-breeding season, 1,514 in the breeding season and 1,037 in the post-breeding season. This is equivalent to an increase in baseline mortality of 1.04% in the pre-breeding season, 3.71% in the breeding season and 0.80% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 3,572, which equates to an increase in baseline mortality of 2.76% ( Table 11.72   Open ▸ ).

 

Table 11.73:
Kittiwake Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

Table 11.73: Kittiwake Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

 

  1. Without Berwick Bank, the estimated collision mortality for kittiwake is 842 individuals in the pre-breeding season, 897 in the breeding season and 847 in the post-breeding season. This is equivalent to an increase in baseline mortality of 0.86% in the pre-breeding season, 2.20% in the breeding season and 0.65% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 2,586 individuals, which equates to an increase in baseline mortality of 2.00% ( Table 11.73   Open ▸ ).
  2. The cumulative collision mortality therefore represents an increase in mortality of over 1% of baseline mortality during the pre-breeding, breeding season and annually with Berwick Bank and the breeding season and annually excluding Berwick Bank. Therefore, to further assess the significance of this effect, a PVA has been carried out for kittiwake as described in volume 3, appendix 11.5.
                        PVA Assessment Including Berwick Bank
  1. When considering the impact during the pre-breeding season on the regional population defined for the pre-breeding season, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.891 ( Table 11.74   Open ▸ ). The median population size was therefore projected to be 10.94% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 42.92. In terms of the population size, this means that the median of the impacted population fell within the 42nd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as outlined within volume 3, appendix 11.5, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.997 ( Table 11.74   Open ▸ ) which translates to a median reduction of 0.32% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.74:
Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Pre-breeding Season

Table 11.74: Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Pre-breeding Season

 

  1. When considering the impact during the breeding season on the regional population defined for the breeding season, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.626 ( Table 11.75   Open ▸ ). The median population size was therefore projected to be 37.38% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 21.76 In terms of the population size, this means that the median of the impacted population fell within the 21st percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.987 ( Table 11.75   Open ▸ ) which translates to a median reduction of 1.29% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.75:
Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Breeding Season

Table 11.75: Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Breeding Season

 

  1. When considering the annual impact on the annual regional population, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.728 ( Table 11.76   Open ▸ ). The median population size was therefore projected to be 27.25% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 30.92. In terms of the population size, this means that the median of the impacted population fell within the 30th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.991 ( Table 11.76   Open ▸ ) which translates to a median reduction of 0.88% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.76:
Kittiwake 35 Year Cumulative PVA Results for Displacement Impacts Including Berwick Bank on an Annual Basis

Table 11.76: Kittiwake 35 Year Cumulative PVA Results for Displacement Impacts Including Berwick Bank on an Annual Basis

 

                        PVA Assessment Excluding Berwick Bank
  1. When considering the impact during the breeding season on the regional population defined for the breeding season, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank excluded, the PVA predicted that the CPS was 0.759 ( Table 11.77   Open ▸ ). The median population size was therefore projected to be 24.13% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 33.0. In terms of the population size, this means that the median of the impacted population fell within the 33rd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.992 ( Table 11.77   Open ▸ ) which translates to a median reduction of 0.76% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.77:
Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Excluding Berwick Bank during the Breeding Season

Table 11.77: Kittiwake 35 Year Cumulative PVA Results for Collision Impacts Excluding Berwick Bank during the Breeding Season

 

  1. When considering the annual impact on the annual regional population, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank excluded, the PVA predicted that the CPS was 0.795 ( Table 11.78   Open ▸ ). The median population size was therefore projected to be 20.53% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 36.32. In terms of the population size, this means that the median of the impacted population fell within the 36th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.994 ( Table 11.78   Open ▸ ) which translates to a median reduction of 0.64% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.78:
Kittiwake 35 Year Cumulative PVA Results for Displacement Impacts Excluding Berwick Bank on an Annual Basis

Table 11.78: Kittiwake 35 Year Cumulative PVA Results for Displacement Impacts Excluding Berwick Bank on an Annual Basis

 

                        Magnitude of impact
  1. The estimated mortality resulting from collision during operation and maintenance was assessed for each season, and also on an annual basis by combining seasonal impacts and comparing them against the largest regional seasonal population (as set out in volume 3, appendix 11.2).
  2. Based on the PVA results for the pre-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the kittiwake population was perceived as low.
  3. Based on the PVA results for the breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the kittiwake population was perceived as low.
  4. Based on the collision assessment, with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, for the post-breeding season the magnitude of impact on the kittiwake population is considered to be of low magnitude.
  5. Based on the PVA results, on an annual basis with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on kittiwake populations is considered to be of low magnitude.
  6. Based on the collision assessment for the pre-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the kittiwake population was perceived as low.
  7. Based on the PVA results for the breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment was perceived as low.
  8. Based on the collision assessment, with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, for the post-breeding season the magnitude of impact on the kittiwake population is considered to be of low magnitude.
  9. Based on the PVA results, on an annual basis with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on kittiwake populations is considered to be of low magnitude.
  10. Kittiwake populations have been declining within the UK with Burnell et al. (2023) reporting that the population has decreased by 21%. However, it is evident that this decline is attributed to the presence of other pressures such as poor prey resources which can impact productivity (Furness and Tasker, 2000; Frederiksen et al., 2008; Carroll et al., 2017) and challenges from climate change (Heath et al, 2012). The PVA indicates that cumulative mortality attributed to offshore wind farms would have a minimal impact on the overall population trajectory.
  11. The cumulative effect is predicted to be of national spatial extent, long-term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

                        Sensitivity of the receptor

  1. Kittiwake was rated as highly vulnerable to collision impacts by Wade et al. (2016), due to the proportion of flights likely to occur at potential risk height and percentage of time in flight. In terms of nocturnal activity rate, kittiwake are considered to have a medium rate of activity at night with a score of three (out of five) (Wade et al. 2016).
  2. Kittiwake lay two eggs and breed from the age of three onwards, typically living on average for 12 years (Burnell et al., 2023). Kittiwake have undergone decreases of approximately 57% in Scotland since the early 2000s. Surveys managed by the RSPB in 2023 have recorded indicative increases of 8% across a number of sites in Britain in 2023 when compared against a pre-HPAI baseline (Tremlett et al., 2024). Overall, kittiwake is deemed to have low recoverability.
  3. Kittiwake is a qualifying interest for several SPAs likely to be connected to the Array (within the mean-max + SD foraging range), with several non-SPA colonies also within range and so the species is considered to be of international conservation value. Refer to table 6.2 of volume 3, appendix 11.1 for details of SPAs with connectivity to the Array with regards to kittiwake.
  4. Kittiwake is deemed to be of high vulnerability, low recoverability and international value. The sensitivity of the receptor is therefore considered to be high.

                        Significance of the effect

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of minor to moderate adverse significance. However, considering pre-breeding season mortality rates fell below 1%, along with the PVA results indicating a low impact with and without Berwick Bank, the impact is considered minor. It is therefore deemed appropriate to categorise the impact as having a minor adverse significance, which is not significant in EIA terms.
                        Further mitigation and residual effect
  1. No offshore ornithology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 11.10) is not significant in EIA terms.
                        Herring Gull
  1. The estimated collision mortalities of herring gull for the purpose of estimating cumulative collisions impacts are given in Table 11.79   Open ▸ . Estimated collisions for projects are those presented by Berwick Bank (SSE Renewables, 2022), for which NatureScot has not raised any concerns or noted any errors. In addition, estimates have been obtained from Green Volt Offshore Wind Farm (Green Volt, 2023), Pentland Floating Offshore Wind (Pentland Floating Offshore Wind Farm, 2022), West of Orkney (Offshore Wind Power Limited, 2023), North Falls (North Falls, 2023), Five Estuaries (Five Estuaries, 2023) and Outer Dowsing (Outer Dowsing, 2023) offshore wind farms, as those projects had not published their estimates at the time of the Berwick Bank application.

 

Table 11.79:
Herring Gull Cumulative Collision Mortalities

Table 11.79: Herring Gull Cumulative Collision Mortalities

 

  1. The cumulative collision mortality is given in Table 11.80   Open ▸ (with Berwick Bank included) and Table 11.81   Open ▸ (with Berwick Bank excluded).

 

Table 11.80:
Herring Gull Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

Table 11.80: Herring Gull Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

 

  1. With Berwick Bank, the estimated cumulative collision mortality for herring gull is 64 individuals in the breeding season and 437 individuals in the non-breeding season. This is equivalent to an increase in baseline mortality of 2.73% in the breeding season and 0.55% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 501, which equates to an increase in baseline mortality of 0.63% ( Table 11.80   Open ▸ ).

 

Table 11.81:
Herring Gull Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

Table 11.81: Herring Gull Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

 

  1. Without Berwick Bank, the estimated collision mortality for herring gull is 21 individuals in the breeding season and 430 in the non-breeding season. This is equivalent to an increase in baseline mortality of 0.91% in the breeding season and 0.54% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 451 individuals, which equates to an increase in baseline mortality of 0.57% ( Table 11.81   Open ▸ ).
  2. The cumulative collision mortality represents an increase in mortality of over 1% of baseline mortality in the breeding season only, and only when including Berwick Bank. Therefore, to further assess the significance of this effect, a PVA has been carried out for herring gull as described in volume 3, appendix 11.5.
                        PVA Assessment Including Berwick Bank
  1. When considering the impact during the breeding season on the regional population defined for the breeding season, using the NatureScot avoidance rates (0.994 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.815 ( Table 11.82   Open ▸ ). The median population size was therefore projected to be 18.34% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 33.32. In terms of the population size, this means that the median of the impacted population fell within the 33rd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.994 ( Table 11.82   Open ▸ ) which translates to a median reduction of 0.57% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.82:
Herring gull 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Breeding Season

Table 11.82: Herring gull 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Breeding Season

 

                        Magnitude of impact
  1. The estimated mortality resulting from collision during operation and maintenance was assessed for each season, and also on an annual basis by combining seasonal impacts and comparing them against the largest regional seasonal population (as set out in volume 3, appendix 11.2).
  2. Based on the PVA results for the breeding season with Berwick Bank included and following the NatureScot Approach using a 0.994 avoidance rate, the impact from the cumulative assessment on the herring gull population was perceived as low.
  3. Based on the collision assessment, with Berwick Bank included and following the NatureScot Approach using a 0.994 avoidance rate, for the non-breeding season the magnitude of impact on the herring gull population is considered to be of low magnitude
  4. Based on the collision assessment, with Berwick Bank included and following the NatureScot Approach using a 0.994 avoidance rate, on an annual basis the magnitude of impact on the herring gull population is considered to be of low magnitude
  5. Based on the collision assessment results for the breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.994 avoidance rate, the impact from the cumulative assessment on the herring gull population was perceived as low.
  6. Based on the collision assessment, with Berwick Bank excluded and following the NatureScot Approach using a 0.994 avoidance rate, for the non-breeding season the magnitude of impact on the herring gull population is considered to be of low magnitude
  7. Based on the collision assessment, with Berwick Bank excluded and following the NatureScot Approach using a 0.994 avoidance rate, on an annual basis the magnitude of impact on the herring gull population is considered to be of low magnitude
  8. Herring gull populations have been declining within the UK with Burnell et al. (2023) reporting that the population has decreased by around 30%, with colonies within Scotland down 44% (NatureScot, 2024). However it is evident that this decline is attributed to the presence of other pressures such as food availability, bycatch, disease and pollution (Gorski et al. 1977; Zydelis et al. 2013). The PVA indicates that cumulative mortality attributed to offshore wind farms would have a minimal impact on the overall population trajectory.
  9. Due to the minimal level of change to baseline conditions, the cumulative effect is predicted to be of national spatial extent, long-term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

                        Sensitivity of the receptor

  1. Herring gull was rated as one of the most vulnerable seabird species to collision impacts by Wade et al. (2016), due to the proportion of flights likely to occur at potential risk height and percentage of time in flight. In terms of nocturnal activity rate, herring gull are considered to have a medium rate of activity at night with a score of three (out of five) (Wade et al. 2016).
  2. As herring gull is a qualifying interest for two SPAs likely to be connected to the Array (within the mean-max + SD foraging range of Fowlsheugh SPA and Buchan Ness to Collieston Coast SPA) with multiple non-SPA colonies within range, the species is considered to be of international value. Refer to Table 6.7 of volume 3, appendix 11.1 for details of SPAs with connectivity to the Array with regards to herring gull.
  3. Herring gull lay up to three eggs and breed from the age of four onwards, typically living on average for 12 years (Burnell et al., 2023). Natural nesting colonies of herring gull have undergone decreases of approximately 44% in Scotland since the early 2000s, whereas urban-nesting populations have increased considerably. Given that the urban population is small compared to the natural population (Burnell et al., 2023), the overall trend is likely to be a decline. Surveys managed by the RSPB in 2023 have recorded indicative declines of 7% across a number of sites in Britain in 2023 when compared against a pre-HPAI baseline (Tremlett et al., 2024). Overall herring gull is considered to have low recoverability.
  4. Herring gull is deemed to be of very high vulnerability, low recoverability and international value. The sensitivity of the receptor is therefore, considered to be high.

                        Significance of the effect

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of minor to moderate adverse significance. However, considering the non-breeding season and annual mortality rates are below 1% of baseline mortality, along with the PVA results indicating a low impact with and without Berwick Bank, the effect should be considered minor. It is therefore deemed appropriate to categorise the impact as having a minor adverse significance, which is not significant in EIA terms.
                        Further mitigation and residual effect
  1. No offshore ornithology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 11.10) is not significant in EIA terms.
                        Gannet
  1. The estimated collision mortalities of gannet for the purpose of estimating cumulative collisions impacts are given in Table 11.83   Open ▸ . Estimated collisions for projects are those presented by Berwick Bank (SSE Renewables, 2022), for which NatureScot has not raised any concerns or noted any errors. In addition, estimates have been obtained from Green Volt Offshore Wind Farm (Green Volt, 2023), Pentland Floating Offshore Wind (Pentland Floating Offshore Wind Farm, 2022), West of Orkney (Offshore Wind Power Limited, 2023), North Falls (North Falls, 2023), Five Estuaries (Five Estuaries, 2023) and Outer Dowsing (Outer Dowsing, 2023) offshore wind farms, as those projects had not published their estimates at the time of the Berwick Bank application.

 

Table 11.83:
Gannet Cumulative Collision Mortalities

Table 11.83: Gannet Cumulative Collision Mortalities

 

  1. The cumulative collision mortality is given in Table 11.84   Open ▸ (with Berwick Bank included) and Table 11.85   Open ▸ (with Berwick Bank excluded).

 

Table 11.84:
Gannet Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

Table 11.84: Gannet Cumulative Collision Mortality Estimates Inclusive of Berwick Bank

 

  1. With Berwick Bank, the estimated collision mortality for gannet is 241 individuals in the pre-breeding season, 673 individuals in the breeding season and 1,052 in the post-breeding season. This is equivalent to an increase in baseline mortality of 0.50% in the pre-breeding season, 0.46% in the breeding season and 1.20% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 1,966, which equates to an increase in baseline mortality of 1.34% ( Table 11.84   Open ▸ ).

 

Table 11.85:
Gannet Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

Table 11.85: Gannet Cumulative Collision Mortality Estimates Exclusive of Berwick Bank

 

  1. Without Berwick Bank, the estimated collision mortality for gannet is 237 individuals in the pre-breeding season, 882 individuals in the breeding season and 655 in the post-breeding season. This is equivalent to an increase in baseline mortality of 0.49% in the pre-breeding season, 0.59% in the breeding season and 0.75% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 1,775 individuals, which equates to an increase in baseline mortality of 1.20% ( Table 11.85   Open ▸ ).
  2. The cumulative collision mortality therefore represents an increase in annual mortality of over 1% of baseline mortality, both with Berwick Bank included for the post-breeding season and on an annual basis. With Berwick Bank excluded, the 1% threshold is surpassed on an annual basis only. Therefore, to further assess the significance of this effect, a PVA has been carried out for gannet as described in volume 3, appendix 11.5.
                        PVA Assessment Including Berwick Bank
  1. When considering the impact on the post-breeding regional population, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.831 ( Table 11.87   Open ▸ Table 11.87   Open ▸ ). The median population size was therefore projected to be 16.89% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 22.16. In terms of the population size, this means that the median of the impacted population fell within the 22nd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.995 ( Table 11.87   Open ▸ ) which translates to a median reduction of 0.51% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.86:
Gannet 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Post-breeding Season

Table 11.86: Gannet 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank during the Post-breeding Season

 

  1. When considering the annual impact on the annual regional population, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank included, the PVA predicted that the CPS was 0.820 ( Table 11.87   Open ▸ ). The median population size was therefore projected to be 18.0% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 20.76. In terms of the population size, this means that the median of the impacted population fell within the 20th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.995 ( Table 11.87   Open ▸ ) which translates to a median reduction of 0.55% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.87:
Gannet 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank on an Annual Basis

Table 11.87: Gannet 35 Year Cumulative PVA Results for Collision Impacts Including Berwick Bank on an Annual Basis

 

                        PVA Assessment Excluding Berwick Bank
  1. When considering the annual impact on the annual regional population, using the NatureScot avoidance rates (0.993 avoidance) and with Berwick Bank excluded, the PVA predicted that the CPS was 0.836 ( Table 11.88   Open ▸ ). The median population size was therefore projected to be 16.38% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 22.56. In terms of the population size, this means that the median of the impacted population fell within the 22nd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.995 ( Table 11.88   Open ▸ ) which translates to a median reduction of 0.50% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.88:
Gannet 35 Year Cumulative PVA Results for Collision Impacts Excluding Berwick Bank on an Annual Basis

Table 11.88:  Gannet 35 Year Cumulative PVA Results for Collision Impacts Excluding Berwick Bank on an Annual Basis

 

                        Magnitude of impact
  1. The estimated mortality resulting from collision during operation and maintenance was assessed for each season, and also on an annual basis by combining seasonal impacts and comparing them against the largest regional seasonal population (as set out in volume 3, appendix 11.2).
  2. Based on the collision assessment for the pre-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population was perceived as low.
  3. Based on the collision assessment for the breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population was perceived as low.
  4. Based on the PVA results for the post-breeding season with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population is considered to be of low magnitude
  5. Based on the PVA results, with Berwick Bank included and following the NatureScot Approach using a 0.993 avoidance rate, on an annual basis the magnitude of impact on the gannet population is considered to be of low magnitude
  6. Based on the collision assessment for the pre-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population was perceived as low.
  7. Based on the collision assessment for the breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population was perceived as low.
  8. Based on the collision assessment for the post-breeding season with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, the impact from the cumulative assessment on the gannet population was perceived as low.
  9. Based on the PVA results, with Berwick Bank excluded and following the NatureScot Approach using a 0.993 avoidance rate, on an annual basis the magnitude of impact on the gannet population is considered to be of low magnitude.
  10. The cumulative effect is predicted to be of national spatial extent, long-term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

                        Sensitivity of the receptor

  1. Although the latest scientific guidance showed the species to display a high level of macro-avoidance (Peschko et al., 2020), the species is rated as relatively vulnerable to collision impacts by Wade et al. (2016).
  2. Gannet is a qualifying interest for several SPAs likely to be connected to the Array (within the mean-max + SD foraging range). The species is therefore considered to be of international value. Refer to Table 6.30 of volume 3, appendix 11.1 for details of SPAs with connectivity to the Array with regards to gannet.
  3. Gannet have low reproductive potential given a typical age of first breeding of five years and typically laying only a single egg per breeding season. However, although gannet has a low reproductive potential, the species has demonstrated a consistent increasing trend in abundance since the 1990’s (JNCC, 2020).. It is of note that the species has suffered from the outbreak of avian flu during the 2022 breeding season (Pearce-Higgins et al., 2023), with declines of 25% recorded at certain sites in Britain in 2023 when compared against a pre-HPAI baseline (Tremlett et al., 2024). Therefore, whilst the overall population has shown steady growth, HPAI has led to some short-term declines. Therefore, overall gannet is deemed to have low recoverability.
  4. Gannet is deemed to be of high vulnerability, low recoverability and international value. The sensitivity of the receptor is therefore considered to be high.

                        Significance of the effect

  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be high. The effect will, therefore, be of minor to moderate adverse significance. However, considering the pre-breeding, breeding and post-breeding season mortality rates fell below 1%, along with the PVA results indicating a low impact with and without Berwick Bank, the impact is considered minor. It is therefore deemed appropriate to categorise the impact as having a minor adverse significance, which is not significant in EIA terms.
                        Further mitigation and residual effect
  1. No offshore ornithology mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 11.10) is not significant in EIA terms.

combined displacement and Collision with Wind Turbines

  1. There is no cumulative displacement and/or collision impact from the Proposed onshore application. Whilst there may be a displacement resulting from maintenance/repair activities associated with the Proposed offshore export cable(s), any such displacement would be highly localised and temporary in nature, and is therefore expected to be negligible.
  2. There is potential for combined cumulative displacement and collision with regards to kittiwake and gannet, as a result of construction and operational activities associated with the Array cumulatively with other developments.
  3. Combined collision and displacement mortality has been calculated using an additive approach as advised by NatureScot in their representation in response to the Ossian Array Scoping Report (refer to section 11.5).
  4. It is recognised that assessing these two potential impacts together could amount to double counting, as birds that are subject to displacement could not be subject to potential collision risk as they are already assumed to have not entered the Array. Equally, birds estimated to be subject to collision risk mortality would not be subjected to displacement mortality as well. The results presented in this section are therefore considered highly precautionary, especially gannet due to high displacement rates.
  5. Currently, no more refined method to consider displacement and collision together has been agreed with NatureScot and therefore the precautionary and highly unlikely additive approach is presented in this assessment.

                        Tier 1 and Tier 2

                        Kittiwake
  1. The combined cumulative displacement and collision mortality is given in Table 11.89   Open ▸ (with Berwick Bank included) and Table 11.90   Open ▸ (with Berwick Bank excluded). Displacement mortality is calculated using 30% displacement and a range of 1% to 3% mortality in all seasons, in line with guidance (NatureScot, 2023h). Additionally, the Applicant’s Approach which utilises a 30% displacement rate and 1% mortality rate is presented.

 

Table 11.89:
Kittiwake Combined Cumulative Displacement and Collision Mortality Estimates Inclusive of Berwick Bank

Table 11.89: Kittiwake Combined Cumulative Displacement and Collision Mortality Estimates Inclusive of Berwick Bank

 

  1. With Berwick Bank, the estimated combined displacement and collision mortality for kittiwake, following the NatureScot Approach, is 1,225 to 1,634 individuals in the pre-breeding season, 1,703 to 2,080 individuals in the breeding season and 1,285 to 1,781 individuals in the post-breeding season. This is equivalent to an increase in baseline mortality of 1.25% to 1.67% in the pre-breeding season, 4.18% to 5.10% in the breeding season and 0.99% to 1.37% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 4,213 to 5,495 individuals, which equates to an increase in baseline mortality of 3.25% to 4.24% ( Table 11.89   Open ▸ ).
  2. When following the Applicant’s Approach, the estimated combined displacement and collision mortality with Berwick Bank, for kittiwake is 1,225 individuals in the pre-breeding season, 1,703 individuals in the breeding season and 1,285 individuals in the post-breeding season. This is equivalent to an increase in baseline mortality of 1.25% in the pre-breeding season, 4.18% in the breeding season and 0.99% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 4,213 individuals, which equates to an increase in baseline mortality of 3.25%.

 

Table 11.90:
Kittiwake Combined Cumulative Displacement and Collision Mortality Estimates Exclusive of Berwick Bank

Table 11.90: Kittiwake Combined Cumulative Displacement and Collision Mortality Estimates Exclusive of Berwick Bank

 

  1. Without Berwick Bank, the estimated combined displacement and collision mortality for kittiwake is 1,005 to 1,331 individuals in the pre-breeding season, 1,023 to 1,273 in the breeding season and 1,062 to 1,490 in the post-breeding season. This is equivalent to an increase in baseline mortality of 1.03% to 1.36% in the pre-breeding season, 2.51% to 3.12% in the breeding season and 0.82% to 1.15% in the post-breeding season. On an annual basis, the number of mortalities is estimates as 3,089 to 4,094 individuals, which equates to an increase in baseline mortality of 2.38% to 3.16% ( Table 11.90   Open ▸ Table 11.90   Open ▸ ).
  2. When following the Applicant’s Approach, the estimated combined displacement and collision mortality without Berwick Bank, for kittiwake is 1,005 individuals in the pre-breeding season, 1,023 individuals in the breeding season and 1,062 individuals in the post-breeding season. This is equivalent to an increase in baseline mortality of 1.03% in the pre-breeding season, 2.51% in the breeding season and 0.82% in the post-breeding season. On an annual basis, the number of mortalities is estimated as 3,089 individuals, which equates to an increase in baseline mortality of 2.38%.
  3. The cumulative combined displacement and collision mortality represents an increase in mortality of over 1% of baseline mortality, both with and without Berwick Bank, across all seasons when applying NatureScot displacement rates. When following the Applicant’s Approach, the 1% threshold was surpassed in the pre-breeding season, breeding season and on an annual basis. Therefore, to further assess the significance of this effect, a PVA has been carried out for kittiwake as described in volume 3, appendix 11.5.
                        PVA Assessment Including Berwick Bank
  1. When considering the impact during the pre-breeding season on the regional population defined for the pre-breeding season, using the NatureScot avoidance rates (0.993 avoidance, 30% displacement and 1% to 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was between 0.870 to 0.831 ( Table 11.91   Open ▸ ). The median population size was therefore projected to be 12.97% to 16.93% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 41.40 to 38.76. In terms of the population size, this means that the median of the impacted population fell within the 41st and 38th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was between 0.996 to 0.995 ( Table 11.91   Open ▸ ) which translates to a median reduction of 0.39% to 0.51% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.
  2. When considering the impact during the pre-breeding season on the regional population defined for the pre-breeding season, using the Applicant’s displacement rates and the NatureScot avoidance rates (0.993 avoidance, 30% displacement and 1% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.870 ( Table 11.91   Open ▸ ). The median population size was therefore projected to be 12.98% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 41.16. In terms of the population size, this means that the median of the impacted population fell within the 41st percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.996 ( Table 11.91   Open ▸ ) which translates to a median reduction of 0.39% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.91:
Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Pre-breeding Season

Table 11.91: Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Pre-breeding Season

 

  1. When considering the impact during the breeding season on the regional population defined for the breeding season, using the NatureScot Approach (0.993 avoidance, 30% displacement and 1% to 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was between 0.591 to 0.525 ( Table 11.92   Open ▸ ). The median population size was therefore projected to be 40.90% to 47.46% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 19.52 to 15.40. In terms of the population size, this means that the median of the impacted population fell within the 19th and 15th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary, between the 19th and 15th percentiles of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. As outlined within volume 3, appendix 11.5, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was between 0.986 to 0.982 ( Table 11.92   Open ▸ ) which translates to a median reduction of 1.45% to 1.77% in population growth rate after 35 years. Such a decrease indicates that this level of impact would adversely affect the population.
  2. When considering the impact during the breeding season on the regional population defined for the breeding season, using the Applicant’s displacement rates and the NatureScot avoidance rates (0.993 avoidance, 30% displacement and 1% mortality) and with Berwick Bank Included, the PVA predicted that the CPS was 0.591 ( Table 11.92   Open ▸ ). The median population size was therefore projected to be 40.90% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 19.56. In terms of the population size, this means that the median of the impacted population fell within the 19th percentile of the unimpacted population (a value of 50 would indicate that they are the same). Notably, the median of the impacted population fell close to the lower boundary, between the 19th percentile of the unimpacted population. Whilst this is within the margin of error, this proximity suggests there could be an adverse effect to the population. As stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.986 ( Table 11.92   Open ▸ ) which translates to a median reduction of 1.45% in population growth rate after 35 years. Such a decrease indicates that this level of impact would adversely affect the population.

 

Table 11.92:
Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Breeding Season

Table 11.92: Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Breeding Season

 

  1. When considering the impact during the post-breeding season on the regional population defined for the post-breeding season, using the most extreme NatureScot scenario (0.993 avoidance, 30% displacement and 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.854 ( Table 11.93   Open ▸ ). The median population size was therefore projected to be 14.64% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 40.20. In terms of the population size, this means that the median of the impacted population fell within the 40th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.996 ( Table 11.93   Open ▸ ) which translates to a median reduction of 0.44% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would likely remain undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.93:
Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Post-breeding Season

Table 11.93: Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank during the Post-breeding Season

 

  1. When considering the annual impact on the annual regional population, using the NatureScot Approach (0.993 avoidance, 30% displacement and 1% to 3% mortality) and with Berwick Bank included, the PVA predicted that the CPS was between 0.687 to 0.612 ( Table 11.94   Open ▸ ). The median population size was therefore projected to be between 31.28% to 38.78% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 28.12 to 22.92. In terms of the population size, this means that the median of the impacted population fell within the 28th and 22nd percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was between 0.990 to 0.987 ( Table 11.94   Open ▸ ) which translates to a median reduction of 1.04% to 1.35% in population growth rate after 35 years. Under the most extreme NatureScot scenario of 30% displacement and 3% mortality alongside collision, this level of impact indicates that there could be an adverse affect on the population.
  2. When considering the annual impact on the annual regional population, using the Applicant’s displacement rate and the NatureScot avoidance rates (0.993 avoidance, 30% displacement and 1% mortality) and with Berwick Bank included, the PVA predicted that the CPS was 0.687 ( Table 11.94   Open ▸ ). The median population size was therefore projected to be 31.28% smaller than the unimpacted population over a 35 year time period, with a 50th centile value of 28.08 In terms of the population size, this means that the median of the impacted population fell within the 28th percentile of the unimpacted population (a value of 50 would indicate that they are the same). This suggests that the impacted scenario was still within the margin of error of the non-impacted scenario, and therefore there would likely be no adverse effect to the population. However, as stated, the CPGR is considered a more robust metric compared to the CPS in this analysis due to the models being conducted with density independence, in line with NatureScot (2023k) guidance. The PVA model predicted that the CPGR was 0.990 ( Table 11.94   Open ▸ ) which translates to a median reduction of 1.04% in population growth rate after 35 years. Such a decrease indicates that this level of impact would not adversely affect the population and would only result in a slight reduction in the growth rate currently seen in the BDMPS population and would therefore be undetectable against natural population fluctuations. Furthermore, it is not expected to significantly alter the background mortality rate.

 

Table 11.94:
Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank on an Annual Basis

Table 11.94: Kittiwake 35 Year Cumulative PVA Results for Combined Displacement and Collision Impacts Including Berwick Bank on an Annual Basis