Magnitude of impact

The estimated mortality resulting from displacement 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 11.3, and summarised in Table 11.23 Open ▸ ).
Based on the PVA results using a 60% displacement and 5% mortality rate of the NatureScot Approach with Berwick Bank included the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
Based on the displacement assessment using a 60% displacement and 3% mortality rate of the NatureScot Approach with Berwick Bank included the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
Based on the displacement assessment using a 50% displacement and 1% mortality rate of the Applicant Approach with Berwick Bank included the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
Based on the PVA results using a 60% displacement and 5% mortality rate of the NatureScot Approach with Berwick Bank excluded, the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
Based on the displacement assessment using a 60% displacement and 3% mortality rate of the NatureScot Approach with Berwick Bank excluded, the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
Based on the displacement assessment using a 50% displacement and 1% mortality rate of the Applicant Approach with Berwick Bank excluded, the magnitude of impact on the puffin population during the breeding season is considered to be of low magnitude.
During the breeding season, the Applicant Approach is regarded as informative, particularly because the rates utilised are derived from post-construction studies conducted over multiple years (see paragraph 144 to 147). However, even under the NatureScot Approach and incorporating the most extreme scenario of 60% displacement and 5% mortality, the impact is considered to be of low magnitude, irrespective of whether Berwick Bank is included or excluded from the analysis.
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

Puffin are considered to be moderately vulnerable to disturbance (Wade et al., 2016). Behavioural responses to underwater and airborne sounds resulting from construction activities are unknown. Although puffin are likely to respond to visual stimuli during the construction phase, the impacts of disturbance/displacement are short-term and puffin have the ability to return to the baseline abundance and distribution after construction (MacArthur Green, 2023).
Puffin have a low reproductive potential (i.e. typically laying only one egg and not breeding until five years old) (Robinson, 2005). Given puffin nest in burrows, and often in inaccessible locations, abundance estimates are relatively infrequent. The long-term pattern indicates a population increase since the counts conducted for Operation Seafarer (1969/70) but small declines in recent years (JNCC, 2021; Burnell, 2023). Puffin is therefore assessed as having low recoverability.
Puffin 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 value. The population recorded during baseline surveys of the Array was found to be of regional importance. Therefore, puffin is considered to be of international value.
Puffin is deemed to be of medium vulnerability, limited potential 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, due to the PVA results concluding there to be a low impact both with and without Berwick Bank and following both the NatureScot and Applicant’s Approach, it is considered that minor adverse significance is appropriate, 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.

Razorbill

The estimated abundance of razorbill for the purpose of estimating displacement impacts is given in Table 11.59:. Estimated abundances 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 11.59: Razorbill Cumulative Abundance Estimates

Project	Season
	Breeding	Post-breeding	Winter	Pre-breeding
Aberdeen	161	64	7	26
Beatrice	N/A (outside foraging range)	833	555	833
Blyth Demo Phase 1	N/A (outside foraging range)	91	61	91
Blyth Demo Phase 2 and 3	N/A (outside foraging range	-	-	-
Dudgeon Extension and Sheringham Shoal Extension	N/A (outside foraging range)	4,500	1,531	464
Dogger Bank (Creyke Beck) A	N/A (outside foraging range)	1,576	1,728	4,149
Dogger Bank (Creyke Beck) B	N/A (outside foraging range)	2,097	2,143	5,119
Dogger Bank C (Teesside A)	N/A (outside foraging range)	310	959	1,919
Dogger Bank Sofia (Teesside B)	N/A (outside foraging range)	592	1,426	2,953
Dudgeon	N/A (outside foraging range)	346	745	346
East Anglia ONE	N/A (outside foraging range)	26	155	336
East Anglia ONE North	N/A (outside foraging range)	85	54	207
East Anglia THREE	N/A (outside foraging range)	1,122	1,499	1,524
East Anglia TWO	N/A (outside foraging range)	44	136	230
Five Estuaries	N/A (outside foraging range)	284	1,046	756
Forthwind Demonstration Project	-	-	-	-
Galloper	N/A (outside foraging range)	43	106	394
Gunfleet Sands 3 Demonstration Project	N/A (outside foraging range)	-	-	-
Green Volt Offshore Wind Farm	457	56	15	28
Hornsea Project Four	N/A (outside foraging range)	3,590	474	371
Hornsea Project One	N/A (outside foraging range)	4,812	1,518	1,803
Hornsea Project Three	N/A (outside foraging range)	2,020	3,649	2,105
Hornsea Project Two	N/A (outside foraging range)	4,221	720	1,668
Humber Gateway	N/A (outside foraging range)	20	13	20
Hywind	30	719	10	N/A
Inch Cape Offshore Wind Farm	1,436	2,870	651	N/A
Kentish Flats and Extension	N/A (outside foraging range)	-	-	-
Kincardine Offshore Wind Farm	22	-	-	-
London Array	N/A (outside foraging range)	20	14	21
Moray East	N/A (outside foraging range)	1,103	30	168
Moray West	N/A (outside foraging range)	3,544	184	3,585
Neart na Gaoithe	331	5,492	508
Norfolk Boreas	N/A (outside foraging range)	263	1,065	345
North Falls (PEIR)	N/A (outside foraging range)	266	2,565	1,860
Norfolk Vanguard	N/A (outside foraging range)	866	839	924
Outer dowsing	N/A (outside foraging range)	2339	2570	5299
Pentland Floating Offshore Wind	N/A (outside foraging range)	N/A (outside BDMPS)	N/A (outside BDMPS)	N/A (outside BDMPS)
Race Bank	N/A (outside foraging range)	42	28	42
Rampion	N/A (outside foraging range)	66	1,244	3,327
Rampion 2	N/A (outside foraging range)	26	1,193	6,303
Seagreen 1 and 1A Offshore Wind Farm	9,574	assessed as breeding and non-breeding season	2,375	assessed as breeding and non-breeding season
Sheringham Shoal	N/A (outside foraging range)	1,343	211	30
Teesside	N/A (outside foraging range)	61	2	20
Thanet	N/A (outside foraging range)	-	14	21
Triton Knoll	N/A (outside foraging range)	254	855	117
West of Orkney	N/A (outside foraging range)	N/A (outside BDMPS)	N/A (outside BDMPS)	N/A (outside BDMPS)
Westermost Rough	N/A (outside foraging range)	121	152	91
Total	12,011	46,127	33,050	47,495
Berwick Bank	4,040	8,849	1,399	7,480
Ossian	2,608	1,493	138	224
Total (including Berwick Bank)	18,659	56,469	34,587	55,199
Total (excluding Berwick Bank)	14,619	47,620	33,188	47,719

The cumulative displacement mortality is given in Table 11.60 Open ▸ (with Berwick Bank included) and Table 11.61 Open ▸ with Berwick Bank excluded). Mortality is calculated using 60% displacement and a range of 3% to 5% mortality in the breeding season and 1% to 3% mortality in the non-breeding seasons, in line with guidance (NatureScot, 2023h). Additionally, the Applicant’s Approach which utilises a 50% displacement rate and 1% mortality rate is presented.

Table 11.60: Razorbill Cumulative Displacement Mortality Estimates Inclusive of Berwick Bank

Season	Regional Baseline		Cumulative Displacement Mortality (Developer Approach)	Cumulative Displacement Mortality (NatureScot Approach)	Increase in Baseline Mortality (Applicant’s Approach) (%)	Increase in Baseline Mortality (NatureScot Approach) (%)
Season	Population	Baseline Mortality	Cumulative Displacement Mortality (Developer Approach)	Cumulative Displacement Mortality (NatureScot Approach)	Increase in Baseline Mortality (Applicant’s Approach) (%)	Increase in Baseline Mortality (NatureScot Approach) (%)
Pre-breeding	591,874	101,980	276	331 to 994	0.271	0.325 to 0.974
Breeding	54,552	9,399	93	336 to 560	0.993	3.573 to 5.956
Post-breeding	591,874	101,980	282	339 to 1,016	0.277	0.332 to 0.997
Non-breeding	218,622	37,669	173	208 to 623	0.459	0.551 to 1.653
Annual	591,874	101,980	825	1,213 to 3,192	0.809	1.190 to 3.130

With Berwick Bank, the estimated displacement mortality for razorbill, following the NatureScot Approach, is 331 to 994 individuals in the pre-breeding season, 336 to 560 individuals in the breeding season, 339 to 1,016 individuals in the post-breeding season and 208 to 623 individuals in the non-breeding season. This is equivalent to an increase in baseline mortality of 0.33% to 0.97% in the pre-breeding season, 3.57% to 5.96% in the breeding season, 0.33% to 1.00% in the post-breeding season and 0.55% to 1.65% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 1,213 to 3,192 individuals, which equates to an increase in baseline mortality of 1.19% to 3.13% ( Table 11.60 Open ▸ ).
When following the Applicant’s Approach, the estimated displacement mortality with Berwick Bank, for razorbill is 276 individuals in the pre-breeding season, 93 individuals in the breeding season, 282 individuals in the post-breeding season and 173 individuals in the non-breeding season. This is equivalent to an increase in baseline mortality of 0.27% in the pre-breeding season, 0.99% in the breeding season, 0.28% in the post-breeding season and 0.46% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 825 individuals, which equates to an increase in baseline mortality of 0.81%.

Table 11.61: Razorbill Cumulative Displacement Mortality Estimates Exclusive of Berwick Bank

Season	Regional Baseline		Cumulative Displacement Mortality (Applicant’s Approach)	Cumulative Displacement Mortality (NatureScot Approach)	Increase in Baseline Mortality (Applicant’s Approach) (%)	Increase in Baseline Mortality (NatureScot Approach) (%)
Season	Population	Baseline Mortality	Cumulative Displacement Mortality (Applicant’s Approach)	Cumulative Displacement Mortality (NatureScot Approach)	Increase in Baseline Mortality (Applicant’s Approach) (%)	Increase in Baseline Mortality (NatureScot Approach) (%)
Pre-breeding	591,874	101,980	239	286 to 859	0.234	0.281 to 0.842
Breeding	54,552	9,399	73	263 to 439	0.778	2.800 to 4.666
Post-breeding	591,874	101,980	238	286 to 857	0.233	0.280 to 0.841
Non-breeding	218,622	37,669	166	199 to 597	0.441	0.529 to 1.586
Annual	591,874	101,980	716	1,034 to 2,752	0.702	1.014 to 2.699

Without Berwick Bank and using the NatureScot rates, the estimated displacement mortality for razorbill is 286 to 859 individuals in the pre-breeding season, 263 to 439 individuals in the breeding season, 286 to 857 individuals in the post-breeding season and 199 to 597 individuals in the non-breeding season. This is equivalent to an increase in baseline mortality of 0.28% to 0.84% in the pre-breeding season, 2.80% to 4.67% in the breeding season, 0.28% to 0.84% in the post-breeding season and 0.53% to 1.59% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 1,034 to 2,752 individuals, which equates to an increase in baseline mortality of 1.01% to 2.70% ( Table 11.61 Open ▸ ).
When following the Applicant’s Approach, the estimated displacement mortality without Berwick Bank, for razorbill is 239 individuals in the pre-breeding season, 73 individuals in the breeding season, 238 individuals in the post-breeding season and 166 individuals in the non-breeding season. This is equivalent to an increase in baseline mortality of 0.23% in the pre-breeding season, 0.78% in the breeding season, 0.23% in the post-breeding season and 0.44% in the non-breeding season. On an annual basis, the number of mortalities is estimated as 716 individuals, which equates to an increase in baseline mortality of 0.70%.
The estimated cumulative displacement mortality therefore represents an increase in mortality of over 1% of baseline mortality when applying the NatureScot Approach range with Berwick Bank, as well as the upper range of the NatureScot Approach without Berwick Bank during the breeding season and on an annual basis. Therefore, to further assess the significance of this effect, a PVA has been carried out for razorbill as described in volume 3, appendix 11.5.

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