5.5.4. Displacement and Collision Combined

The apportioned annual mortality rates for displacement and collision are extracted from the relevant information within sections 5.5.2 and 5.5.3, respectively.

Operation and maintenance phase

Buchan Ness to Collieston Coast SPA

Kittiwake (seabird assemblage feature only)

The combined mortality from displacement and collision (using a simple additive approach of the values in Table 5.63 Open ▸ and Table 5.117 Open ▸ ) is presented in Table 5.158 Open ▸ . The approach sums the collision and disturbance impacts, with potential for double counting inherent in that approach.

Table 5.158: Kittiwake Combined Displacement and Collision Mortalities Apportioned To the Buchan Ness to Collieston Coast SPA In-Combination Totals

Project(s)	Adult Mortalities
	Pre-Breeding Season		Breeding Season		Post-Breeding Season		Annual Total
	Low	High	Low	High	Low	High	Low	High
UK North Sea projects	29.4	30.2	25.7	29.0	20.9	28.8	76.0	88.0
Green Volt Offshore Wind Farm	0.1	0.1	1.3	1.5	0.1	0.1	1.5	1.7
West of Orkney Wind Farm	1.0	1.2	0.2	0.3	0.8	0.9	1.9	2.3
Pentland Floating Offshore Wind	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Outer Dowsing	N/A	N/A	N/A	N/A	N/A	N/A	1.5	1.5
Berwick Bank Offshore Wind Farm	4.7	7.6	5.2	8.5	2.5	5.0	12.4	21.1
Ossian	0.1	0.3	1.4	6.2	0.0	0.2	1.6	6.6
Total (Including Berwick Bank Offshore Wind Farm)	30.5	31.7	28.7	37.0	21.8	30.0	82.5	100.2
Total (Excluding Berwick Bank Offshore Wind Farm)	25.8	24.1	23.5	28.5	19.3	25.0	70.1	79.1

With a population of 22,590 breeding adults (Burnell et al., 2023), 70.1 to 100.2 additional mortalities represents a 0.310 to 0.443 percentage point increase in mortality rates. Therefore, PVA has been carried out both with and without Berwick Bank Offshore Wind Farm and for the high and low scenarios, to further assess the total in-combination impact.
The PVA results are summarised in Table 5.159 Open ▸ . Full details are available in appendix 3B.

Table 5.159: Summary of PVA Results for In-Combination Combined Displacement and Collision Impacts on Kittiwake at the Buchan Ness to Collieston Coast SPA

Scenario	Approach	Adult Mortality	Citation Population (Breeding Adults)	Recent Population (Burnell et al., 2023) (Breeding Adults)	Median Unimpacted Population After 35 Years	Median Impacted Population After 35 Years	Median CGR	Median CPS
Including Berwick Bank Offshore Wind Farm	Low	82.5	60,904	22,590	21,365	18,214	0.996	0.856
Including Berwick Bank Offshore Wind Farm	High	100.2				17,624	0.995	0.828
Excluding Berwick Bank Offshore Wind Farm	Low	70.1				18,676	0.996	0.876
Excluding Berwick Bank Offshore Wind Farm	High	79.1				18,404	0.996	0.861

The kittiwake population of the Buchan Ness to Collieston Coast SPA has declined significantly between its citation level of 60,904 breeding adults and Seabird Census counts of 22,590 breeding adults (Burnell et al., 2023), and is assessed as being in “Unfavourable No Change” condition (NatureScot, ND). There have however been recent signs of slight recovery, with 13,547 AONs (27,094 individuals) recorded in 2023 (Tremlett et al, 2024).
The PVA results show that the kittiwake population is expected to remain relatively stable under the counterfactual (no impact) scenario. Under the impacted scenarios, the CGR is 0.995 to 0.996 under both the high and low approach if Berwick Bank Offshore Wind Farm’s impacts are included, or 0.996 if Berwick Bank Offshore Wind Farm’s impacts are excluded. This leads to a CPS after 35 years of 0.828 to 0.876 – i.e. the population size would be 12.4% to 17.2% smaller than the counterfactual population size.
Whilst this level of impact is small, it is not negligible and in the context of a population that is already declining, the additional mortality from the Array in combination with other projects and plans would appear to have the potential to adversely affect the likelihood of the site meeting its conservation objectives for all assessment scenarios and both with and without Berwick Bank Offshore Wind Farm. Therefore, it is concluded that there is a potential AEOI to the kittiwake feature of the Buchan Ness to Collieston Coast SPA as a result of combined displacement and collision impacts from the Array in-combination with other developments. However, kittiwake is not a qualifying feature it its own right, and instead only qualifies as a named component of the breeding seabird assemblage.

Breeding Seabird Assemblage

Of the components of the seabird assemblage, kittiwake was the only species for which a potential LSE2 was identified. As detailed above, there is expected to be a significant impact on the kittiwake population. The kittiwake population at citation was significantly higher than the current population, and at citation kittiwake was the most numerous breeding species at this site, whilst based on Seabirds Count (Burnell et al., 2023) guillemot are now more numerous. Whilst the magnitude of the impact would not be deemed sufficient to risk entirely losing kittiwake as a viable component of the assemblage, the decline is sufficient to adversely affect the total population size of the overall assemblage.
Therefore, it is concluded that there is a potential AEOI to the seabird assemblage feature of the Buchan Ness to Collieston Coast SPA as a result of the impact of collision from the Array in-combination with other developments.

East Caithness Cliffs SPA

Kittiwake

The combined mortality from displacement and collision (using a simple additive approach of the values in Table 5.69 Open ▸ and Table 5.120 Open ▸ ) is presented in Table 5.160 Open ▸ . The approach sums the collision and disturbance impacts, with potential for double counting inherent in that approach.

Table 5.160: Kittiwake Combined Displacement and Collision Mortalities Apportioned to the East Caithness Cliffs SPA In-Combination Totals

Project(s)	Adult Mortalities
	Pre-Breeding Season		Breeding Season		Post-Breeding Season		Annual Total
	Low	High	Low	High	Low	High	Low	High
UK North Sea projects	94.5	129.2	123.9	189.2	67.6	92.8	286.0	411.2
Green Volt Offshore Wind Farm	0.3	0.4	0.9	1.0	0.4	0.5	1.6	1.9
West of Orkney Wind Farm	3.1	3.7	2.9	3.8	2.5	2.9	8.5	10.5
Pentland Floating Offshore Wind	0.0	0.0	0.7	0.7	0.0	0.0	0.7	0.7
SEP & DEP	0.1	0.1	0.0	0.0	0.3	0.3	0.4	0.4
Outer Dowsing	N/A	N/A	N/A	N/A	N/A	N/A	4.9	4.9
Berwick Bank Offshore Wind Farm	15.0	24.1	0.4	0.6	8.1	16.3	23.5	41.0
Ossian	0.2	0.9	0.7	2.8	0.1	0.6	1.0	4.2
Total (Including Berwick Bank Offshore Wind Farm)	98.2	134.3	129.0	197.5	70.9	97.1	303.1	433.8
Total (Excluding Berwick Bank Offshore Wind Farm)	83.2	110.2	128.6	196.9	62.8	80.8	279.6	392.8

With a population of 48,958 breeding adults (Burnell et al., 2023), 279.6 to 433.8 additional mortalities represents a 0.571 to 0.886 percentage point increase in mortality rates. Therefore, PVA has been carried out both with and without Berwick Bank Offshore Wind Farm and for the high and low scenarios, to further assess the total in-combination impact.
The PVA results are summarised in Table 5.161 Open ▸ . Full details are available in appendix 3B.

Table 5.161: Summary of PVA Results for In-Combination Combined Displacement and Collision Impacts on Kittiwake at the East Caithness Cliffs SPA

Scenario	Approach	Adult Mortality	Citation Population (Breeding Adults)	Recent Population (Burnell et al., 2023) (Breeding Adults)	Median Unimpacted Population After 35 Years	Median Impacted Population After 35 Years	Median CGR	Median CPS
Including Berwick Bank Offshore Wind Farm	Low	303.1	65,000	48,958	46,244	35,624	0.993	0.771
Including Berwick Bank Offshore Wind Farm	High	433.8				31,707	0.990	0.687
Excluding Berwick Bank Offshore Wind Farm	Low	279.6				36,174	0.993	0.784
Excluding Berwick Bank Offshore Wind Farm	High	392.8				32,720	0.991	0.710

The kittiwake population of the East Caithness Cliffs SPA has declined slightly between its citation level of 65,000 breeding adults and recent counts of 48,958 breeding adults (Burnell et al., 2023), although it is assessed as being in “Favourable Maintained” condition (NatureScot, ND).
The PVA results show that the kittiwake population is expected to remain relatively stable under the counterfactual (no impact) scenario. Under the impacted scenarios, the CGR ranges from 0.990 to 0.993. This leads to a CPS after 35 years of 0.687 to 0.784 – i.e. the population size would be 22.6% to 31.3% smaller than the counterfactual population size.
In the context of a population that is already declining, the additional mortality from the Array in combination with other projects and plans would appear to have the potential to adversely affect the likelihood of the site meeting its conservation objectives for all assessment scenarios and both with and without Berwick Bank Offshore Wind Farm. Therefore, it is concluded that there is a potential AEOI to the kittiwake feature of the East Caithness Cliffs SPA as a result of combined displacement and collision impacts from the Array in-combination with other developments.

Breeding Seabird Assemblage

Of the components of the seabird assemblage, kittiwake was the only species for which a potential LSE2 was identified for combined displacement and collision risk. As detailed above, there is expected to be a significant impact on the kittiwake population. The kittiwake population at citation was significantly higher than the current population (Burnell et al., 2023). Whilst the magnitude of the impact would not be deemed sufficient to risk entirely losing kittiwake as a viable component of the assemblage, the decline is sufficient to adversely affect the total population size of the overall assemblage.
Therefore, it is concluded that there is a potential AEOI to the seabird assemblage feature of the East Caithness Cliffs SPA as a result of the impact of combined displacement and collision from the Array in-combination with other developments.

Farne Islands SPA

Kittiwake (seabird assemblage component only)

The combined mortality from displacement and collision (using a simple additive approach of the values in Table 5.72 Open ▸ and Table 5.123 Open ▸ ) is presented in Table 5.162 Open ▸ . The approach sums the collision and disturbance impacts, with potential for double counting inherent in that approach.

Table 5.162: Kittiwake Combined Displacement and Collision Mortalities Apportioned to the Farne Islands SPA In-Combination Totals

Project(s)	Adult Mortalities
	Pre-Breeding Season		Breeding Season		Post-Breeding Season		Annual Total
	Low	High	Low	High	Low	High	Low	High
UK North Sea projects	8.2	11.1	19.2	31.7	5.8	7.9	33.2	50.7
Green Volt Offshore Wind Farm	0.0	0.0	0.1	0.1	0.0	0.0	0.1	0.1
West of Orkney Wind Farm	0.3	0.3	0.0	0.0	0.2	0.2	0.5	0.6
Pentland Floating Offshore Wind	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Outer Dowsing	0.3	0.3	0.2	0.2	0.1	0.1	0.6	0.6
Berwick Bank Offshore Wind Farm	1.4	2.2	19.2	31.7	0.7	1.4	21.3	35.3
Ossian	0.0	0.1	0.5	2.1	0.0	0.1	0.5	2.2
Total (Including Berwick Bank Offshore Wind Farm)	8.8	11.8	20.0	34.1	6.1	8.3	34.9	54.2
Total (Excluding Berwick Bank Offshore Wind Farm)	7.4	9.6	0.8	2.4	5.4	6.9	13.6	18.9

With a population of 8,804 breeding adults (Burnell et al., 2023), 13.6 to 54.2 additional mortalities represents a 0.155 to 0.616 percentage point increase in mortality rates. Therefore, PVA has been carried out both with and without Berwick Bank Offshore Wind Farm and for the high and low scenarios, to further assess the total in-combination impact.
The PVA results are summarised in Table 5.163 Open ▸ . Full details are available in appendix 3B.

Table 5.163: Summary of PVA Results for Combined Displacement and Collision Impacts In-Combination on Kittiwake at the Farne Islands SPA

Scenario	Approach	Adult Mortality	Citation Population (Breeding Adults)	Recent Population (Burnell et al., 2023) (Breeding Adults)	Median Unimpacted Population After 35 Years	Median Impacted Population After 35 Years	Median CGR	Median CPS
Including Berwick Bank Offshore Wind Farm	Low	34.9	8,241	8,804	8,312	7,018	0.995	0.844
Including Berwick Bank Offshore Wind Farm	High	54.2				6,376	0.993	0.768
Excluding Berwick Bank Offshore Wind Farm	Low	13.6				7,771	0.998	0.936
Excluding Berwick Bank Offshore Wind Farm	High	18.9				7,609	0.997	0.912

The kittiwake population of the Farne Islands SPA has increased slightly from its citation level of 8,241 breeding adults to recent counts of 8,804 breeding adults (Burnell et al., 2023).
The PVA results show that the kittiwake population is expected to remain relatively stable under the counterfactual (no impact) scenario. Under the impacted scenarios, the CGR is 0.993 to 0.998. This leads to a CPS after 35 years of 0.768 to 0.936 – i.e. the population size would be 23.2% to 6.4% smaller than the counterfactual population size.
It should be noted that the approach to assessment of combined displacement and collision impacts is considered highly precautionary, as the simple additive approach has the potential to double count impacts.
If Berwick Bank Offshore Wind Farm is excluded, the impact of displacement from the Array in combination with other projects is predicted to make no material impact on the kittiwake population compared to the counterfactual scenario, and it can be concluded, beyond reasonable scientific doubt, that there is no potential for an AEOI on the kittiwake feature of the Farne SPA as a result of displacement and collision from the Array in-combination with other developments.
However, if Berwick Bank Offshore Wind Farm is included, whilst the level of impact is still small, it is no longer considered negligible and the additional mortality from the Array in-combination with other projects and plans would appear to have the potential to adversely affect the size of the kittiwake population. However, kittiwake is not a qualifying feature it its own right, and instead only qualifies as a named component of the breeding seabird assemblage.

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