3.4. Displacment and Mortality Rates used for assessment

For both displacement and mortality rates, a sub-set of the most likely species-specific rates were highlighted in each species matrix. These include the displacement and mortality rates used in both the Scoping Approach and the Developer Approach (Table 3.5).
A detailed justification of the displacement and mortality rates selected for the Developer approach can be found in Annex G. Displacement and mortality rates used for the Scoping Approach were as advised in the Scoping Opinion.
Assessment of displacement during the non-breeding season was not required for puffin, in either approach, as advised through the Scoping Opinion (4 February 2022). Lower mortality rates were advised for auk species in the non-breeding season in the Scoping Opinion, based on birds being less constrained to nest sites and no longer central-placed foragers. For the Scoping Approach, both advised mortality rates have been assessed and potential mortalities due to displacement identified in the relevant matrices. A displacement rate of 60% has been applied, as advised in the NatureScot scoping representation (December 2021).
For the Developer Approach, a displacement rate of 50% and mortality rate of 1% for auks was considered suitably precautionary for both the breeding and non-breeding season. APEM (2022) undertook a review of auk displacement rates, and the Developer Approach aligns with their recommended maximum rate.
For the Developer Approach, the displacement and mortality rates for puffin (50% and 1% respectively) follow rates applied at the Norfolk Vanguard Offshore Wind Farm (MacArthur Green, 2019a). The displacement rate for gannet (70%) was as advised in the Scoping Opinion (4 February 2022), whilst the mortality rate for gannet (1%) was chosen on the basis of previous recommendations from Natural England at the same development (MacArthur Green, 2019b).
The displacement rate for kittiwake (30%) was advised in the Scoping Opinion (4 February 2022) and is consistent with previous advice on Forth and Tay Projects (Marine Scotland, 2017); this has been applied in both the Scoping and Developer Approach. However, the Developer Approach applies a single mortality rate of 2%, which is within the range advised under the Scoping Approach (1-3%). The mortality rate of 2% follows previous advice from the Marine Scotland on previous Forth & Tay projects (Marine Scotland, 2017).
In addition, the Applicant has further applied the Matrix method to auks using a more nuanced approach; with lower displacement rates applied to the 2km buffer than the Development Array. The relevant methods and results are presented in Annex C and are discussed within Annex G.

Table 3.4: Displacement and mortality rates used for the Scoping Approach (Scoping Opinion 4 February 2022) and the Developer Approach.

Species	Displacement Rate	Mortality Rate – Breeding Season	Mortality Rate – Non-breeding Seasons
Scoping Opinion (February 2022)
Guillemot, Razorbill & Puffin	60%	3% and 5%	1% and 3% (Puffin not assessed)
Gannet	70%	1% and 3%	1% and 3%
Kittiwake	30%	1% and 3%	1% and 3%
Developer Approach
Guillemot and Razorbill	50% within WF area and 2km buffer 1	1% 1	1% 1
Puffin	50% within WF area & 2km buffer 2	1% 2	Not assessed
Gannet	70%	1% 3	1% 3
Kittiwake	30% 4	2% 4	Not assessed

1 Recommended maximum displacement rate from 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

2 Recommended displacement rates from MacArthur Green (2019a). Norfolk Vanguard Offshore Wind Farm. The Applicant Responses to First Written Questions. Appendix 3.3 – Operational Auk and Gannet Displacement: update and clarification

3 Natural England recommended displacement and mortality rates for Gannet for Norfolk Vanguard Offshore Wind Farm. MacArthur Green (2019b). Norfolk Vanguard Offshore Wind Farm Offshore Ornithology Assessment Update for Deadline 6.

4 Based on MS Scoping Opinion for Forth & Tay projects (2017)

4. Results

4.1. Displacement Matrices

The displacement matrices provide, for each species and relevant bio-season, the estimated mortality of birds predicted to occur due to displacement, as determined by the relevant specified rates of displacement and mortality (Table 3.4).
Displacement matrices for each species, in each bio-season and in both the Berwick Bank Development Array and the Berwick Bank Development Array plus a 2 km buffer are presented in Table 4.1 to Table 4.22.
Each cell presents potential bird mortality following displacement from the proposed Berwick Bank OWF during a bio-season given; i) the seasonal mean peak population within the impacted area; ii) the percentage assumed to be displaced from the impacted area; and iii) the assumed percentage mortality amongst the displaced birds. The outputs highlighted in colour are those based on the displacement and mortality rates in Table 3.4 and are deemed the ‘most realistic’ mortality estimates as advised by the: i) Scoping Opinion (highlighted in dark teal) and ii) the Developer Approach (highlighted in orange). Outputs highlighted in light teal reflect potential uncertainty associated with the selected figures, as advised by the SNCB (2017) guidance with regards to presenting the matrices. No adjustments for age classes of birds have been made.

Kittiwake

Table 4.1: Potential kittiwake mortality following displacement from the Berwick Bank Development Array in the breeding season. Estimates considered, in light of empirical evidence, to represent the most realistic scenarios are colour coded, with dark teal representing rates advised by the Scoping Opinion; orange representing rates defined by the Developer Approach; and light teal representing uncertainty around these figures.

Kittiwake (Breeding season)	Mortality Level (% of displaced birds at risk of mortality)
Displacement Level (% of all birds on site)		0%	1%	2%	3%	4%	5%	10%	15%	20%	30%	50%	80%	100%
	0%	0	0	0	0	0	0	0	0	0	0	0	0	0
	10%	0	18	35	52	69	86	172	258	344	516	860	1376	1720
	20%	0	35	69	104	138	172	344	516	688	1032	1720	2752	3439
	30%	0	52	104	155	207	258	516	774	1032	1548	2580	4127	5159
	40%	0	69	138	207	276	344	688	1032	1376	2064	3439	5503	6878
	50%	0	86	172	258	344	430	860	1290	1720	2580	4299	6878	8597
	60%	0	104	207	310	413	516	1032	1548	2064	3095	5159	8254	10317
	70%	0	121	241	362	482	602	1204	1806	2408	3611	6018	9629	12036
	80%	0	138	276	413	551	688	1376	2064	2752	4127	6878	11005	13756
	90%	0	155	310	465	619	774	1548	2322	3095	4643	7738	12380	15475
	100%	0	172	344	516	688	860	1720	2580	3439	5159	8597	13756	17194

Table 4.2: Potential kittiwake mortality following displacement from the Berwick Bank Development Array plus 2 km buffer in the breeding season. Estimates considered, in light of empirical evidence, to represent the most realistic scenarios are colour coded, with dark teal representing rates advised by the Scoping Opinion; orange representing rates defined by the Developer Approach; and light teal representing uncertainty around these figures.

Kittiwake (Breeding season)	Mortality Level (% of displaced birds at risk of mortality)
Displacement Level (% of all birds on site)		0%	1%	2%	3%	4%	5%	10%	15%	20%	30%	50%	80%	100%
	0%	0	0	0	0	0	0	0	0	0	0	0	0	0
	10%	0	22	43	64	85	106	212	318	423	635	1058	1692	2115
	20%	0	43	85	127	170	212	423	635	846	1269	2115	3383	4229
	30%	0	64	127	191	254	318	635	952	1269	1903	3172	5074	6343
	40%	0	85	170	254	339	423	846	1269	1692	2537	4229	6766	8457
	50%	0	106	212	318	423	529	1058	1586	2115	3172	5286	8457	10571
	60%	0	127	254	381	508	635	1269	1903	2537	3806	6343	10148	12685
	70%	0	148	296	444	592	740	1480	2220	2960	4440	7400	11839	14799
	80%	0	170	339	508	677	846	1692	2537	3383	5074	8457	13531	16913
	90%	0	191	381	571	762	952	1903	2855	3806	5709	9514	15222	19027
	100%	0	212	423	635	846	1058	2115	3172	4229	6343	10571	16913	21141

Table 4.3: Potential kittiwake mortality following displacement from the Berwick Bank Development Array in the non-breeding season. Estimates considered, in light of empirical evidence, to represent the most realistic scenarios are colour coded, with dark teal representing rates advised by the Scoping Opinion and light teal representing uncertainty around these figures. A quantitative assessment is not being made for kittiwake in the non-breeding season under the Developer Approach (see Annex G for justification).

Kittiwake (Non-breeding season)	Mortality Level (% of displaced birds at risk of mortality)
Displacement Level (% of all birds on site)		0%	1%	2%	3%	4%	5%	10%	15%	20%	30%	50%	80%	100%
	0%	0	0	0	0	0	0	0	0	0	0	0	0	0
	10%	0	16	32	48	64	80	159	238	317	475	791	1266	1582
	20%	0	32	64	95	127	159	317	475	633	950	1582	2532	3164
	30%	0	48	95	143	190	238	475	712	950	1424	2374	3797	4747
	40%	0	64	127	190	254	317	633	950	1266	1899	3164	5063	6328
	50%	0	80	159	238	317	396	791	1187	1582	2373	3955	6328	7910
	60%	0	95	190	285	380	475	950	1424	1899	2848	4747	7594	9493
	70%	0	111	222	333	443	554	1108	1662	2215	3323	5538	8860	11075
	80%	0	127	254	380	507	633	1266	1899	2532	3797	6328	10125	12656
	90%	0	143	285	428	570	712	1424	2136	2848	4272	7119	11391	14238
	100%	0	159	317	475	633	791	1582	2373	3164	4746	7910	12656	15820

Table 4.4: Potential kittiwake mortality following displacement from the Berwick Bank Development Array plus 2km buffer in the spring migration (non-breeding) period. Estimates considered, in light of empirical evidence, to represent the most realistic scenarios are colour coded, with dark teal representing rates advised by the Scoping Opinion and light teal representing uncertainty around these figures. A quantitative assessment is not being made for kittiwake in the non-breeding season under the Developer Approach (see Annex G for justification).

Kittiwake (Spring migration)	Mortality Level (% of displaced birds at risk of mortality)
Displacement Level (% of all birds on site)		0%	1%	2%	3%	4%	5%	10%	15%	20%	30%	50%	80%	100%
	0%	0	0	0	0	0	0	0	0	0	0	0	0	0
	10%	0	14	28	41	55	69	138	206	275	413	688	1101	1377
	20%	0	28	55	83	110	138	275	413	551	826	1377	2203	2753
	30%	0	41	83	124	165	206	413	619	826	1239	2065	3304	4130
	40%	0	55	110	165	220	275	551	826	1101	1652	2753	4405	5506
	50%	0	69	138	206	275	344	688	1032	1377	2065	3442	5506	6883
	60%	0	83	165	248	330	413	826	1239	1652	2478	4130	6608	8260
	70%	0	96	193	289	385	482	964	1445	1927	2891	4818	7709	9636
	80%	0	110	220	330	441	551	1101	1652	2203	3304	5506	8810	11013
	90%	0	124	248	372	496	619	1239	1858	2478	3717	6195	9912	12389
	100%	0	138	275	413	551	688	1377	2065	2753	4130	6883	11013	13766

Table 4.5: Potential kittiwake mortality following displacement from the Berwick Bank Development Array plus 2km buffer in the autumn migration (non-breeding) period. Estimates considered, in light of empirical evidence, to represent the most realistic scenarios are colour coded, with dark teal representing rates advised by the Scoping Opinion and light teal representing uncertainty around these figures. A quantitative assessment is not being made for kittiwake in the non-breeding season under the Developer Approach (see Annex G for justification).

Kittiwake (Autumn migration)	Mortality Level (% of displaced birds at risk of mortality)
Displacement Level (% of all birds on site)		0%	1%	2%	3%	4%	5%	10%	15%	20%	30%	50%	80%	100%
	0%	0	0	0	0	0	0	0	0	0	0	0	0	0
	10%	0	11	22	34	45	56	112	168	224	336	560	895	1119
	20%	0	22	45	67	90	112	224	336	448	671	1119	1790	2238
	30%	0	34	67	101	134	168	336	504	671	1007	1679	2686	3357
	40%	0	45	90	134	179	224	448	671	895	1343	2238	3581	4476
	50%	0	56	112	168	224	280	560	839	1119	1678	2798	4476	5595
	60%	0	67	134	201	269	336	671	1007	1343	2014	3357	5371	6714
	70%	0	78	157	235	313	392	783	1175	1567	2350	3917	6266	7833
	80%	0	90	179	269	358	448	895	1343	1790	2686	4476	7162	8952
	90%	0	101	201	302	403	504	1007	1511	2014	3021	5036	8057	10071
	100%	0	112	224	336	448	560	1119	1678	2238	3357	5595	8952	11190

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