PVA Assessment Excluding Berwick Bank

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

Scenario	Predicted Mortality (Original Impact) (no. of birds)	Growth Rate (Annual GR)	Median CPGR	Median CPS	U=50%I
NatureScot Approach – 0.993 avoidance rate	897.44	0.9875	0.9924	0.7587	33.0

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

Scenario	Predicted Mortality (Original Impact) (no. of birds)	Growth Rate (Annual GR)	Median CPGR	Median CPS	U=50%I
NatureScot Approach – 0.993 avoidance rate	2,586.30	0.9888	0.9936	0.7947	36.32

Magnitude of impact

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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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

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).
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.
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.
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

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

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

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

Project		Season
Project	Avoidance Rate used in Assessment	Breeding	Non-breeding
Aberdeen	99.5%	4.8	0
Beatrice	99.5%	N/A (outside foraging range)	197.4
Blyth Demo Phase 1	99.5%	N/A (outside foraging range)	2.2
Blyth Demo Phase 2 and 3	unknown	N/A (outside foraging range)	-
Dogger Bank A and B	unknown	N/A (outside foraging range)	-
Dogger C and Sofia	unknown	N/A (outside foraging range)	-
Dudgeon	unknown	N/A (outside foraging range)	-
East Anglia ONE	99.5%	N/A (outside foraging range)	28
East Anglia ONE North	99.5%	N/A (outside foraging range)	0
East Anglia THREE	99.5%	N/A (outside foraging range)	23
East Anglia TWO	99.5%	N/A (outside foraging range)	0.5
Five Estuaries	99.4%	N/A (outside foraging range)	1.52
Forthwind Demonstration Project	uknown	-	-
Galloper	unknown	N/A (outside foraging range)	-
Gunfleet Sands 3 Demonstration Project	unknown	N/A (outside foraging range)	-
Green Volt Offshore Wind Farm	99.4%	N/A (outside foraging range)	5.8
Hornsea Project Four	99.5%	N/A (outside foraging range)	0.9
Hornsea Project One	99.5%	N/A (outside foraging range)	11.6
Hornsea Project Three	99.5%	N/A (outside foraging range)	4
Hornsea Project Two	unknown	N/A (outside foraging range)	-
Hywind	99.5%	0.6	7.8
Inch Cape	99.5%	N/A (outside foraging range)	13.5
Kentish Flats + Extension	99.5%	N/A (outside foraging range)	1.7
Kincardine	99.5%	1	0
Lincs	99.5%	N/A (outside foraging range)	-
London Array	99.5%	N/A (outside foraging range)	-
Moray East	99.5%	N/A (outside foraging range)	-
Moray West	99.5%	N/A (outside foraging range)	1
Neart na Gaoithe	99.5%	5	12.5
N North Falls (PEIR)	99.5%	N/A (outside foraging range)	0.91
Norfolk Boreas	99.5%	N/A (outside foraging range)	5.4
Norfolk Vanguard	99.0%	N/A (outside foraging range)	7.1
Outer Dowsing	99.4%	N/A (outside foraging range)	0.2
Pentland Floating Offshore Wind	unknown	N/A (outside foraging range)	0
Race Bank	99.5%	N/A (outside foraging range)	-
Rampion 1	99.5%	N/A (outside foraging range)	0
Rampion 2	99.5%	N/A (outside foraging range)	28.1
Seagreen 1 and 1A Offshore Wind Farm	unknown	10	21
Sheringham Shoal	99.5%	N/A (outside foraging range)	-
Teesside	99.5%	N/A (outside foraging range)	34.5
Thanet	unknown	N/A (outside foraging range)	19.6
Triton Knoll	unknown	N/A (outside foraging range)	-
West of Orkney	99.5%	N/A (outside foraging range)	-
Westermost Rough	99.5%	N/A (outside foraging range)	0
Total	-	21.4	427.23
Berwick Bank	99.4%	43	7
Ossian	99.5%	0	2.7
Total (including Berwick Bank)	-	64.4	436.93
Total (excluding Berwick Bank)	-	21.4	429.93

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

Season	Regional Baseline		Cumulative Collision Mortality	Increase in Baseline Mortality (%)
Season	Population	Baseline Mortality	Cumulative Collision Mortality	Increase in Baseline Mortality (%)
Breeding	13,836	2,363	64.4	2.725
Non-breeding	466,511	79,680	436.93	0.548
Annual	466,511	79,680	501.33	0.629

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

Season	Regional Baseline		Cumulative Collision Mortality	Increase in Baseline Mortality (%)
Season	Population	Baseline Mortality	Cumulative Collision Mortality	Increase in Baseline Mortality (%)
Breeding	13,836	2,363	21.4	0.906
Non-breeding	466,511	79,680	429.93	0.540
Annual	466,511	79,680	451.33	0.566

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 ▸ ).
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.

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