4.2. Displacement estimates

A summary of the final estimates of likely seabird mortality from displacement derived through the Matrix Approach for each species and bio-season for the Berwick Bank Development Array and Berwick Bank Development Array plus 2km buffer following the Scoping Approach and Developer Approach is shown in Table 4.23.

Table 4.23: Potential bird mortality per bio-season following displacement and barrier effects from the Berwick Bank Development Array and the Berwick Bank Development Array plus 2 km buffer, for the mortality and displacement rates selected in Table 3.4. Figures are presented for both the “Scoping Approach” and the “Developer Approach”. Estimates are separated by a ‘/’ where the Scoping Opinion instructs the use of multiple mortality rates.

Species	Development Array		Development Array + 2 km buffer
	Breeding season	Non-breeding season	Breeding season	Non-breeding season	Spring migration	Winter	Autumn migration
Scoping Approach
Kittiwake	52 / 155	48 / 143	64 / 191	N/A	41 / 124	N/A	34 / 101
Guillemot	1,075 / 1,791	205 / 613	1,335 / 2,225	266 / 795	N/A	N/A	N/A
Razorbill	55 / 92	53 / 157	73 / 122	N/A	45 / 135	8 / 25	53 / 159
Puffin	62 / 102	N/A	82 / 136	N/A	N/A	N/A	N/A
Gannet	26 / 76	8 / 22	34 /100	N/A	2 / 6	N/A	11 / 32
Developer Approach
Kittiwake	104	N/A	127	N/A	N/A	N/A	N/A
Guillemot	299	171	371	221	N/A	N/A	N/A
Razorbill	16	44	21	N/A	37	7	44
Puffin	17	N/A	23	N/A	N/A	N/A	N/A
Gannet	26	8	34	N/A	2	N/A	11

5. Summary

Following the joint SNCB interim advice (SNCBs, 2017), the impact of displacement on seabird species predicted to result from an operational Berwick Bank OWF was assessed using the Matrix method. This approach was agreed with MSS and NatureScot during the Ornithology Roadmap Process (RM1, July 2021). Assessment was conducted on five species: kittiwake, guillemot, razorbill, puffin and gannet. Displacement matrices were created to show the potential bird mortality following displacement, dependent on the percentage of birds considered likely to be displaced and subsequent potential mortality rates. Outputs were generated for each species, in each bio-season, and for two spatial scales: the Berwick Bank Development array and the Berwick Bank Development array plus a 2 km buffer.
Additional analyses using SeabORD for kittiwake and the auks was also conducted (Annex D).
The results for gannet are supplemented with analyses of GPS tagging data from the Bass Rock colony 2010 – 2019 (Annex E).
The Applicant undertook a parallel approach to the assessment, with two sets of final mortality figures selected: one set based on parameters advised by the Scoping Opinion (“Scoping Approach”) and one set based on the parameters considered to be most plausible by the Project and defined as the “Developer Approach”.
The Scoping Approach followed displacement and mortality rates advised within the Scoping Opinion (4 February 2022). Displacement rates of 30% for kittiwake, 60% for guillemot, razorbill and puffin, and 70% for gannet were used. Mortality rates of 1 and 3% were advised for kittiwake and gannet in both the breeding and non-breeding season. Mortality rates of 3 and 5% were advised for all auks (guillemot, razorbill and puffin) in the breeding season and a 1 and 3% mortality rate used for guillemot and razorbill in the non-breeding season. Puffin was not assessed in the non-breeding season.
In contrast, the Developer Approach followed displacement and mortality rates supported by other cited evidence and previous precedents of consented projects. A displacement rate of 30% was used for kittiwake in the breeding season, 50% used for guillemot and razorbill in both breeding and non-breeding seasons, 50% puffin in the breeding season and 70% used for gannet in both breeding and non-breeding seasons. A mortality rate of 1% was used for guillemot, razorbill and gannet in both the breeding and non-breeding season, and for puffin in the breeding season only. Puffin was not assessed in the non-breeding season. A mortality rate of 2% was used for kittiwake in the breeding season. A quantitative assessment was not undertaken for kittiwakes in the non-breeding season.
The final mortality values from displacement selected via the two approaches are presented in Table 4.23.
The mortality estimates arising from both approaches are apportioned to SPA populations (Technical Appendix 11.5: Ornithological Apportioning Technical Report) and used to model impact scenarios in the Population Viability Analyses (Appendix 11.6: Ornithology Population Viability Analysis Technical Report). This includes the breeding season mortality estimates for all species presented here, and the non-breeding mortality estimates for guillemots and puffins. For those species where the autumn and spring passage and winter periods are defined within the non-breeding season (gannet, kittiwake and razorbill), appropriate displacement matrices were conducted for non-breeding seasons defined by Furness (2015).

6. References

APEM (2022). Review of evidence to support auk displacement and mortality rates in relation to offshore wind farms. APEM Scientific Report P00007416. Ørsted, January 2022, Final, 49.

Bradbury, G., Trinder, M., Furness, B., Banks, A.N, Caldow, R.W.G. and Hume, D. (2014). Mapping Seabird Sensitivity to Offshore Wind Farms. PLoS ONE, 9(9): e106366.

Furness R. W., Wade, H. M. and Masden E.A. (2013). Assessing vulnerability of marine bird populations to offshore wind farms. Journal of Environmental Management, 119, 56-66.

MacArthur Green (2019a). Norfolk Vanguard Offshore Wind Farm Offshore Ornithology Assessment Update for Deadline 6.

MacArthur Green (2019b). Norfolk Vanguard Offshore Wind Farm. The Applicant Responses to First Written Questions. Appendix 3.3 - Operational Auk and Gannet Displacement: update and clarification

Marine Scotland (2017). Marine Scotland Licensing Operations Team: Scoping Opinion for Seagreen Phase 1 Offshore Project. Scottish Government, Edinburgh.

NatureScot (2020). Seasonal Periods for Birds in the Scottish Marine Environment. Short Guidance Note Version 2.

Searle, K., Mobbs, D., Butler, A., Bogdanova, M., Freeman, S., Wanless, S. and Daunt, F. (2014). Population consequences of displacement from proposed offshore wind energy developments for seabirds breeding at Scottish SPAs (CR/2012/03). Final Report to Marine Scotland. Marine Scotland, Edinburgh.

SNCB (2017). Joint SNCB Interim Displacement Advice Note. [Online]. JNCC, Natural Resources Wales, Department of Agriculture, Environment and Rural Affairs/Northern Ireland Environment Agency, Natural England and Scottish Natural Heritage. http://jncc.defra.gov.uk/pdf/Joint_SNCB_Interim_Displacement_AdviceNote_2017.pdf. Accessed 28/10/2021.

Vallejo, G., Robbins, J., Hickey, J., Moullier, A., Slater, S., Dinwoodie, I., Cook, G. & Pendlebruy C.Dinwoodie, I. (2022). Sensitivity analysis of parameters and assumptions in the SeabORD model. Natural Power Report to SSE Renewables.

Annex A Design Based Analysis – Monthly Apportioned Population Estimates (Berwick Bank Development Array)

Table A.1: Monthly density and population estimates of kittiwakes in the Berwick Bank Development array, calculated using design-based analysis. Data include “no-identification” birds apportioned to species.

Kittiwake	Density Estimate (birds/ km2)	Lower 95% CI (birds/ km2)	Upper 95% CI (birds/ km2)	Population Estimate (number)	Lower 95% CI (number)	Upper 95% CI (number)	SD	CV (%)
Survey
Mar-19	15.19	8.29	23.38	15358	8377	23629	3977	25.89%
May-19	4.13	2.93	5.57	4176	2958	5632	673	16.1%
Jun-19	2.65	2.09	3.35	2681	2113	3382	319	11.88%
Jul-19	5.02	4.34	5.69	5075	4389	5753	360	7.08%
Aug-19	6.93	5.72	8.22	7004	5783	8307	646	9.21%
Sep-19	2.15	1.45	2.98	2173	1466	3016	410	18.85%
Oct-19	0.62	0.46	0.78	625	467	794	83	13.18%
Nov-19	0.29	0.18	0.41	295	178	415	65	22.03%
Dec-19	0.28	0.15	0.49	288	156	491	90	31.05%
Jan-20	2.19	1.11	3.59	2215	1125	3632	642	28.98%
Feb-20	1.91	0.97	3.08	1929	977	3116	557	28.86%
Mar-20	5.59	4	7.1	5648	4046	7179	796	14.09%
May S01 20	6.53	2.37	11.29	6601	2399	11410	2208	33.45%
May S02 20	8.41	6.19	10.81	8498	6258	10925	1273	14.98%
Jun-20	9.06	7.45	10.72	9159	7534	10841	884	9.65%
Jul-20	8.69	6.95	10.84	8785	7022	10958	1054	11.99%
Aug-20	13.32	9.56	17.38	13464	9666	17568	2033	15.1%
Sep-20	16.11	10.67	22.37	16282	10789	22614	3135	19.25%
Oct-20	1.49	0.88	2.23	1508	885	2255	361	23.89%
Nov-20	4.84	2.72	7.03	4888	2749	7106	1174	24.01%
Dec-20	1.09	0.68	1.63	1104	690	1644	251	22.69%
Jan-21	2.19	1.35	3.22	2210	1369	3257	484	21.87%
Feb-21	2.83	0.58	5.72	2857	586	5785	1445	50.57%
Apr S01 21	6.85	4.91	9.08	6924	4969	9179	1059	15.28%
Apr S02 21	20.7	10.61	32.66	20923	10721	33018	5943	28.4%

Table A.2: Monthly absolute density and population estimates of guillemots in the Berwick Bank Development array, calculated using design-based analysis and adjusted for availability bias. Data include “no-identification” birds apportioned to species.

Guillemot	Adjusted Density Estimate (birds/ km2)	Adjusted Lower 95% CI (birds/ km2)	Adjusted Upper 95% CI (birds/ km2)	Adjusted Population Estimate (number)	Adjusted Lower 95% CI (number)	Adjusted Upper 95% CI (number)	Adjusted SD	Adjusted CV (%)
Survey
Mar-19	12.52	8.67	18.05	12659	8768	18244	2395	18.92%
May-19	29.66	23.38	37.93	29981	23642	38342	4391	14.65%
Jun-19	7.45	4.93	10.5	7535	4977	10614	1512	20.07%
Jul-19	32.12	26.35	38.28	32466	26630	38703	3328	10.25%
Aug-19	35.81	22.12	52.11	36195	22357	52676	8685	24%
Sep-19	5.05	3.9	6.15	5101	3934	6205	583	11.43%
Oct-19	1.99	1.04	3.4	2009	1053	3429	586	29.17%
Nov-19	0.92	0.66	1.21	931	662	1230	134	14.39%
Dec-19	1.8	1.21	2.47	1822	1221	2501	349	19.15%
Jan-20	13.26	8.95	19.43	13406	9048	19643	2705	20.18%
Feb-20	9.45	6.2	12.78	9555	6269	12926	1852	19.38%
Mar-20	31.82	22.15	41.13	32162	22398	41575	4987	15.51%
May S01 20	22.19	12.82	33	22434	12965	33362	5177	23.08%
May S02 20	20.47	13.94	27.91	20690	14085	28214	4120	19.91%
Jun-20	46.98	37.11	57.49	47498	37513	58112	5706	12.01%
Jul-20	11.72	9.13	14.14	11857	9235	14301	1486	12.53%
Aug-20	31.51	27.49	35.26	31851	27796	35641	2179	6.84%
Sep-20	35.52	25.87	45.7	35912	26150	46199	5353	14.91%
Oct-20	3.12	2.33	3.99	3152	2362	4040	458	14.53%
Nov-20	2.22	1.57	3.05	2245	1581	3093	383	17.06%
Dec-20	14.93	9.69	22.15	15099	9793	22400	3416	22.62%
Jan-21	10.77	8.33	13.05	10893	8424	13192	1221	11.21%
Feb-21	6.59	4.12	9.37	6658	4168	9474	1442	21.66%
Apr S01 21	27.45	22.68	32.06	27752	22925	32409	2592	9.34%
Apr S02 21	71.1	50.84	91.42	71881	51383	92410	10741	14.94%

Table A.3: Monthly absolute density and population estimates of razorbills in the Berwick Bank Development array, calculated using design-based analysis and adjusted for availability bias. Data include “no-identification” birds apportioned to species.

Razorbill	Adjusted Density Estimate (birds/ km2)	Adjusted Lower 95% CI (birds/ km2)	Adjusted Upper 95% CI (birds/ km2)	Adjusted Population Estimate (number)	Adjusted Lower 95% CI (number)	Adjusted Upper 95% CI (number)	Adjusted SD	Adjusted CV (%)
Survey
Mar-19	1.53	0.77	2.58	1548	788	2599	463	29.91%
May-19	1.44	1.08	1.91	1458	1090	1926	251	17.22%
Jun-19	0.22	0.05	0.5	226	55	508	136	60.18%
Jul-19	2.53	1.66	3.54	2563	1684	3588	595	23.21%
Aug-19	1.82	1.1	2.64	1838	1113	2663	441	23.99%
Sep-19	1.48	1.06	1.93	1496	1074	1957	274	18.32%
Oct-19	0.87	0.48	1.37	872	482	1381	238	27.29%
Nov-19	0.14	0.07	0.23	141	75	233	35	24.82%
Dec-19	0.46	0.2	0.82	472	197	822	167	35.38%
Jan-20	1.77	0.99	2.63	1794	1000	2663	457	25.47%
Feb-20	1.21	0.78	1.73	1228	788	1749	284	23.13%
Mar-20	6.38	4.19	8.48	6448	4239	8570	1158	17.96%
May S01 20	0.95	0.56	1.43	967	565	1451	264	27.3%
May S02 20	0.57	0.32	0.92	585	318	924	199	34.02%
Jun-20	1.04	0.7	1.44	1049	704	1456	216	20.59%
Jul-20	1.87	1	2.88	1890	1014	2916	582	30.79%
Aug-20	3.48	2.53	4.82	3520	2563	4866	675	19.18%
Sep-20	10.88	7.31	15.12	10994	7387	15290	2330	21.19%
Oct-20	0.87	0.46	1.38	888	464	1395	228	25.68%
Nov-20	0.33	0.17	0.52	331	175	533	92	27.79%
Dec-20	1.82	1.03	2.65	1845	1041	2671	453	24.55%
Jan-21	3.84	2.77	5.23	3889	2797	5280	631	16.23%
Feb-21	1.65	0.9	2.44	1658	916	2460	419	25.27%
Apr S01 21	3.76	2.39	5.46	3805	2416	5517	824	21.66%
Apr S02 21	1.62	1.21	2.07	1633	1229	2087	238	14.57%

Table A.44: Monthly absolute density and population estimates of puffins in the Berwick Bank Development array, calculated using design-based analysis and adjusted for availability bias. Data include “no-identification” birds apportioned to species.

Puffin	Adjusted Density Estimate (birds/ km2)	Adjusted Lower 95% CI (birds/ km2)	Adjusted Upper 95% CI (birds/ km2)	Adjusted Population Estimate (number)	Adjusted Lower 95% CI (number)	Adjusted Upper 95% CI (number)	Adjusted SD	Adjusted CV (%)
Survey
Mar-19	1.36	0.85	1.93	1375	859	1959	314	22.84%
May-19	2.31	1.86	2.81	2342	1881	2836	281	12%
Jun-19	0.38	0.17	0.63	385	177	645	129	33.51%
Jul-19	3.35	2.46	4.25	3381	2484	4296	598	17.69%
Aug-19	3.99	2.98	4.91	4033	3017	4965	569	14.11%
Sep-19	1.08	0.63	1.79	1100	642	1815	368	33.45%
Oct-19	0.29	0.19	0.42	287	190	418	67	23.34%
Nov-19	0.02	0.01	0.05	29	10	51	14	48.28%
Dec-19	0	0	0	0	0	0	0	0
Jan-20	0.06	0.02	0.09	54	26	93	22	40.74%
Feb-20	0.19	0.09	0.33	190	90	330	78	41.05%
Mar-20	0.57	0.29	0.91	576	289	921	157	27.26%
May S01 20	1.9	1.05	2.61	1929	1065	2643	490	25.4%
May S02 20	0.73	0.52	0.94	737	536	955	132	17.91%
Jun-20	0.86	0.59	1.13	864	603	1142	176	20.37%
Jul-20	1.03	0.51	1.79	1049	517	1809	390	37.18%
Aug-20	1.91	1.34	2.62	1927	1356	2648	400	20.76%
Sep-20	13.7	11.47	16.33	13854	11598	16513	1530	11.04%
Oct-20	0.14	0.1	0.19	142	101	188	28	19.72%
Nov-20	0.14	0.07	0.21	143	77	218	45	31.47%
Dec-20	0.03	0.01	0.06	31	15	55	12	38.71%
Jan-21	0.02	0.01	0.05	27	13	47	12	44.44%
Feb-21	0.41	0.26	0.58	412	255	585	109	26.46%
Apr S01 21	0.98	0.64	1.37	992	645	1397	210	21.17%
Apr S02 21	4.8	3.56	6.08	4849	3608	6145	840	17.32%

Table A.5: Monthly density and population estimates of gannets in the Berwick Bank Development array, calculated using design-based analysis. Data include “no-identification” birds apportioned to species.

Gannet	Density Estimate (birds/ km2)	Lower 95% CI (birds/ km2)	Upper 95% CI (birds/ km2)	Population Estimate (number)	Lower 95% CI (number)	Upper 95% CI (number)	SD	CV (%)
Survey
Mar-19	0.27	0.13	0.45	276	136	454	85	30.62%
May-19	0.74	0.48	1.08	751	490	1093	159	21.09%
Jun-19	1.62	1.18	2.17	1641	1198	2190	233	14.2%
Jul-19	3.58	2.94	4.21	3624	2967	4257	324	8.93%
Aug-19	3.37	2.83	3.94	3408	2857	3982	291	8.51%
Sep-19	2.65	2.17	3.24	2684	2196	3278	274	10.17%
Oct-19	0.79	0.62	0.96	799	627	971	94	11.73%
Nov-19	0.16	0.1	0.24	166	99	245	40	23.61%
Dec-19	0	0	0	0	0	0	0	0
Jan-20	0.01	0	0.02	8	0	24	8	99.39%
Feb-20	0.01	0	0.02	8	0	24	8	95.9%
Mar-20	0.26	0.12	0.43	264	120	435	83	31.47%
May S01 20	0.42	0.22	0.68	421	221	688	122	28.9%
May S02 20	0.81	0.57	1.12	823	573	1136	146	17.69%
Jun-20	1.14	0.82	1.54	1153	828	1560	197	17.01%
Jul-20	3.48	2.92	4.1	3520	2951	4141	313	8.87%
Aug-20	2.44	1.84	3.05	2463	1860	3086	320	12.96%
Sep-20	1.42	1.02	1.9	1435	1036	1919	237	16.48%
Oct-20	0.8	0.57	1.06	814	579	1071	130	15.95%
Nov-20	1.23	0.9	1.62	1239	915	1639	185	14.88%
Dec-20	0.19	0.02	0.46	195	23	469	122	62.83%
Jan-21	0.09	0.03	0.15	87	32	148	32	36.12%
Feb-21	0.12	0.01	0.29	127	16	291	71	55.76%
Apr S01 21	0.57	0.43	0.69	576	438	698	69	11.89%
Apr S02 21	1.41	0.42	2.82	1428	421	2849	651	45.57%

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