Project alone: conclusion

2157. It is considered that the predicted levels of impact from the Proposed Development alone on the Troup, Pennan and Lion’s Head SPA guillemot population are of a small scale, as determined by both the Developer and Scoping Approaches. For both the Developer and Scoping Approaches it is also the case that the centile metric indicates a high likelihood of the impacted population being of similar size to the un-impacted population after 35 years. These levels of impact are within the context of an assessment which incorporates high levels of precaution (particularly as determined by the Scoping Approach). Given this, it is concluded that the effects from the Proposed Development alone (as determined by either the Developer or Scoping Approaches) would not result in an adverse effect on this SPA population.

Effects in-combination

Effects of relevance to the in-combination assessment

2158. As detailed above, any effects from the Proposed Development alone on the Troup, Pennan and Lion’s Head SPA guillemot population during construction and decommissioning and resulting from disturbance and changes to prey availability during operation and maintenance will be small and highly localised. As such, there is considered to be no potential for these effect pathways to add to impacts at the population-level that might result from other effects pathways associated with the Proposed Development or from the effects due to other plans and projects.
2159. Therefore, the potential for effects of the Proposed Development to act on the Troup, Pennan and Lion’s Head SPA guillemot population in-combination with other plans and projects is limited to the displacement (inclusive of barrier effects) pathway during operation and maintenance. The following sections consider these potential effects for (the Proposed Development in-combination with the other UK North Sea wind farms.

Displacement/barrier effects – operation and maintenance

2160. As described in Offshore EIA Report annex A of volume 3, appendix 11.6, estimates of displacement mortality during both the breeding and non-breeding periods which had been attributed to the Troup, Pennan and Lion’s Head SPA guillemot population were extracted from the existing assessments for offshore wind farms that are in planning, consented, under construction or in operation. As for the potential displacement mortality estimated for the Proposed Development, the mortality attributed to the SPA population from other offshore wind farms was estimated using the SNCB matrix approach, with details on the displacement and mortality rates that had been applied being available in each case. Thus, it was possible to adjust the estimated mortalities from each of the other projects to align with the displacement and mortality rates on which the Scoping and Developer Approaches are based.
2161. The potential mortality estimates derived for the other projects were combined with those for the Proposed Development to give in-combination estimates for the UK North Sea wind farms according to both the Scoping Approach and Developer Approach.

Table 5.157: Estimated Annual Mortality of Troup, Pennan and Lion’s Head SPA Guillemots as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, In-Combination with other UK North Sea Wind Farms

2162. Incorporating the potential mortality predicted from the displacement effects associated with the other UK North Sea wind farms leads to a fourfold increase in the predicted displacement mortality compared to the Proposed Development alone for each of the Developer and Scoping Approaches (Tables 5.155 and 5.157). The effects attributed to the breeding season account for 38 – 65% of the predicted annual mortality for the Proposed Development in-combination with the other UK North Sea wind farms (with this contribution being lowest for the Developer Approach and highest for the upper range of the Scoping Approach – Table 5.157).
2163. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult guillemots from the Troup, Pennan and Lion’s Head SPA population predicted due to displacement represents between 0.03% of the current adult breeding population at this colony (i.e. 31,893 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, and between 0.07 – 0.15% as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (based on applying a mortality rate of 0.060 – see Table 2.9 in volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult displacement mortality equate to an increase of 0.6% for the Developer Approach and of 1.2 – 2.5% for the lower and upper estimates from the Scoping Approach.
2164. The potential levels of impact on the Troup, Pennan and Lion’s Head SPA guillemot population resulting from the predicted mortality from displacement and barrier effects associated with the Proposed Development in-combination with the other wind farms in the UK North Sea during the operation and maintenance phase are considered in more detail below in the Effects In-Combination: Population-Level Impacts section. This presents the outputs from PVAs of the potential effects of predicted displacement mortality on the SPA population.

In-combination: population-level impacts

2165. As for the Proposed Development alone, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the displacement effects associated with the Proposed Development in-combination with the other UK North Sea wind farms. This was on the basis of the potential mortality as determined by both the Scoping and Developer Approaches (see Table 5.157 above).
2166. The approach to the PVA and the metrics used to summarise the PVA outputs are as described for the Proposed Development alone (see Project Alone: Population-Level Impacts section above).

Table 5.158: Projected 35 Year Population Sizes and Associated PVA Metrics for the Troup, Pennan and Lion’s Head SPA Guillemot Population Under Different Impact Scenarios for the Proposed Development In-Combination with the other UK North Sea Wind Farms

2167. Given that the in-combination effects are inevitably greater than those for the Proposed Development alone, the PVA metrics for the Proposed Development in-combination with the other UK North Sea wind farms suggest greater population-level impacts than as predicted for the Proposed Development alone (compare Table 5.158 with Table 5.156). However, the predicted levels of impact remain relatively small, irrespective of whether these are determined using the Developer or Scoping Approaches.
2168. The CPS values indicate that the SPA population size would be reduced by approximately 1 - 6% after 35 years relative to that in the absence of any wind farm effects, as determined by the Developer and Scoping Approaches (Table 5.158). The associated reduction in annual population growth rate (relative to that predicted under baseline conditions) is 0.1 – 0.2% for the Scoping Approach and is not detectable for the Developer Approach (at least when the CPGR is expressed to three decimal places). The centile values range from 39.5 – 47.5, indicating a considerable overlap in the distributions of the predicted impacted and un-impacted population sizes and, hence, at least a reasonably high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years (Table 5.158).

In-combination: conclusion

2169. On the basis of both the Developer and Scoping Approaches, the potential effects from the Proposed Development in-combination with the other UK North Sea wind farms on the Troup, Pennan and Lion’s Head SPA guillemot population are predicted to be relatively small, with the resultant population-level impacts also predicted to be small. In addition, the PVA metrics indicate at least a reasonably high likelihood of the population being of a similar size to that which would occur in the absence of the wind farm effects after 35 years. These levels of impact are considered within the context of an assessment which incorporates high levels of precaution (particularly as determined by the Scoping Approach).
2170.  Given the above, it is concluded that the effects from the Proposed Development in-combination with other plans and projects would not result in an adverse effect on the Troup, Pennan and Lion’s Head SPA guillemot population, with this conclusion being irrespective of whether the effects are determined by the Developer or Scoping Approaches.

Assessment for the razorbill population

2171. The Troup, Pennan and Lion’s Head SPA razorbill population is currently estimated to number 6,054 individuals, based upon the most recently available count data from 2017 (Offshore EIA Report, volume 3, appendix 11.5). This is higher than the citation level of 4,800 individuals (Table 5.146). Count data for the population are sporadic but indicate that numbers increased markedly between the mid-1980s and early 2000s (with population estimates of 1,647 and 6,644 individuals for 1986 and 2001, respectively) before undergoing a slight decline to the current levels. Despite the fact that numbers are currently above the citation level and that the overall, long-term, trend is increasing, the SPA population is considered to be in ‘unfavourable, declining’ condition.

The potential for impacts on the razorbill population

2172. The Proposed Development and two kilometre buffer around the Proposed Development array area7 do not overlap with the Troup, Pennan and Lion’s Head SPA, so that potential impacts on its razorbill population will only occur as a result of individuals from the colony occurring in the area (or vicinity) of the Proposed Development. Consequently, the main focus of the assessment for this SPA population is concerned with the Conservation Objective to maintain, in the long term, the population of the species as a viable component of the site because the other conservation objectives either apply to the site itself, and not to areas beyond the boundary, or are encompassed by the assessment of this first Conservation Objective (as for the maintain in the long term no significant disturbance of the species, because disturbance would only be considered significant if it caused an adverse effect on the population viability of the qualifying features).
2173. From published information on razorbill foraging ranges generally (Woodward et al. 2019) and evidence from tracking data (Wakefield et al. 2017), it is possible that during the breeding period razorbills from the Troup, Pennan and Lion’s Head SPA occur within the area of the Proposed Development and of the two km buffer around the Proposed Development array area. This is supported by the findings of the apportioning exercise, which estimates that approximately 2% of the razorbills occurring on the Proposed Development array area during the breeding season derive from this SPA colony (Offshore EIA Report, volume 3, appendix 11.5). The breeding period for razorbill is defined as April to mid-August, following the NatureScot (2020) guidance.
2174. Based on the NatureScot scoping advice (volume 3, appendix 6.2 of the Offshore EIA Report), which draws upon the findings from Buckingham et al. (2022), razorbills are assumed to disperse more widely than guillemots during the non-breeding period, with their distribution concentrated in central areas of the North Sea during the mid-winter period. Consequently, it is assumed (for the purposes of the assessment) that during the non-breeding period birds from the Troup, Pennan and Lion’s Head SPA population have the potential to occur within offshore wind farms throughout the UK North Sea waters during the autumn and spring passage periods and in mid-winter (defined as mid-August to October, January to March and November to December, respectively, on the basis of applying the BDMPS defined periods within the context of the overall non-breeding period defined by NatureScot – Furness 2015, NatureScot 2020, Offshore EIA Report, volume 3, appendix 11.5). Given this, the Proposed Development may have potential effects on the Troup, Pennan and Lion’s Head SPA razorbill population during breeding and non-breeding periods.

Project alone: construction and decommissioning

Disturbance

2175. Direct disturbance to razorbills during the construction phase may arise within the Proposed Development array area (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the installation of the wind turbine foundations and other infrastructure, whilst there will also be increased vessel activity along the Proposed Development export cable corridor due to the cable laying activities. The levels of such activities that could arise are outlined in Table 4.1, with these activities occurring during construction campaigns within a construction period of at most eight years duration.
2176. A total of up to 11,482 vessel round trips may occur over the construction phase, whilst it is estimated that a maximum of 134 vessels could occur within the area of the Proposed Development at any one time (Table 4.1). However, this is within the context of high baseline levels of vessel traffic within this area (e.g. surveys recorded an average of 14 vessels per day within a 10 nm buffer around the Proposed Development over a 14-day period in August 2022, whilst also showing an average of three to four vessels intersecting the Proposed Development array area per day over summer – Offshore EIA Report, volume 2, chapter 13).
2177. When using the marine environment (and not at the breeding colony), razorbills are considered to have a moderate sensitivity to such sources of direct disturbance. Thus, reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic assign razorbill as ‘3’ on a five-scale ranking system, where 1 indicates hardly any or limited escape/avoidance behaviour and very short flight distance when approached and 5 indicates strong escape/avoidance behaviour and a large response distance (Garthe and Hüppop 2004, Furness et al. 2013).
2178. The total area to be affected by such disturbance over the full eight years of the construction phase also represents a small proportion of the total area of marine habitat available to razorbills from the Troup, Pennan and Lion’s Head SPA. Thus, the Proposed Development array area encompasses 1,010 km2, whilst the Proposed Development export cable encompasses 168 km2. Together these areas represent approximately 3% of the total breeding season foraging area that is potentially available to the SPA razorbill population, as defined by the generic measure of the species’ mean maximum breeding season foraging range plus 1 SD (i.e. 88.7±75.9 km - Woodward et al. 2019) and assuming that this range is represented by a semicircle to the main seaward side of the colony. Similarly, the Proposed Development array and export cable corridor represent approximately 10% of the breeding season foraging area if considering the mean maximum foraging range only. Additionally, modelling of razorbill foraging distributions, as derived from tracking data from the chick-rearing period, indicates that the Proposed Development array area and Proposed Development export cable corridor have minimal, if any, overlap with waters that are predicted to be used by birds from the Troup, Pennan and Lion’s Head SPA and exclude those areas of predicted greatest usage (Cleasby et al. 2018).
2179. During the non-breeding periods, razorbill distribution is not constrained by the location of the breeding colonies and birds from the SPA population are likely to occur across large parts of the North Sea (Furness 2015, Buckingham et al. 2022) so that the potential for effects of construction-related disturbance is lower than during the breeding season.
2180. In addition to the above, it is important to consider that the construction activities will not occur simultaneously across the entirety of the Proposed Development array area or the Proposed Development export cable corridor but, rather, will be carried out in different areas at different times. Thus, the activities will be concentrated within discrete (often small) parts of these wider areas, and within such areas they will not extend over the full duration of the construction phase, so further reducing the potential to which birds may be subject to disturbance effects. For example, cable laying for the Proposed Development export cable will occur over a total of two years, whilst within the Proposed Development array area it is likely that construction activities would be confined largely to discrete areas at any one time.
2181. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
2182. Given the moderate sensitivity of razorbill to disturbance effects, the large distance of the Proposed Development from the SPA (relative to the estimated razorbill foraging range), the relatively small areas that will be subject to activities with the potential to result in disturbance at any given time during the construction period and the fact that these potential effects will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance to lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population.

Displacement

2183. As detailed above, razorbill is considered to have a moderate sensitivity to disturbance, whilst potential effects of disturbance during the construction and decommissioning phases will only extend across a small part of the wider foraging areas used by the Troup, Pennan and Lion’s Head SPA razorbill population and be limited to, at most, an eight year period during construction (and a likely similar or shorter period during decommissioning). Furthermore, as detailed above, potential effects of disturbance will not occur simultaneously across the entirety of the Proposed Development array area or Proposed Development export cable corridor but, rather, will be carried out in different areas at different times. Thus, at any given time the potential for disturbance effects that could lead to displacement of razorbills from this SPA will be limited to relatively small areas, with the potential effects also being of a temporary nature.
2184. Based upon the above, it is considered that there is relatively little potential for the Troup, Pennan and Lion’s Head SPA razorbill population to be affected by displacement during the construction or decommissioning phases, with any such effects only extending across relatively small areas and tending to be temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related displacement to lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population.

Changes to prey availability

2185. Sandeels are key prey for razorbills, with a range of other species taken including sprat and juvenile herring (del Hoyo et al., 1996). Indirect effects on razorbills may arise as a result of changes in the availability, distribution, or abundance of these species during the construction and decommissioning phases of the Proposed Development. Reduction or disruption to prey availability may cause displacement from foraging grounds or reduced energy intake, affecting survival rates or productivity in the Troup, Pennan and Lion’s Head SPA razorbill population in the short-term.
2186. During construction and decommissioning there are a number of ways in which effects on key prey species of seabirds may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to Prey Availability for the St Abb’s Head to Fast Castle SPA kittiwake population. The evidence base and context for assessing the potential for such effects to have impacts on the Troup, Pennan and Lion’s Head SPA razorbill population are as for the St Abb’s Head to Fast Castle SPA razorbill population (and are detailed above in the equivalent section for that SPA population). Additionally, the relatively large distance of the Proposed Development from the Troup, Pennan and Lion’s Head SPA is relevant because it reduces the likelihood that razorbills from this SPA will use the Proposed Development (Offshore EIA Report, volume 3, appendix 11.5).
2187. Given this, it is considered that there is relatively little potential for the Troup, Pennan and Lion’s Head SPA razorbill population to be affected by changes to prey availability during the construction and decommissioning phases, with any such effects being largely intermittent across a relatively small spatial extent, with most effects temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population.

Project alone: operation and maintenance

Disturbance

2188. Vessel use and associated activities within the Proposed Development array area and export cable corridor during the operation and maintenance phase may lead to direct disturbance of razorbills from Troup, Pennan and Lion’s Head SPA. As described in the section on Project Alone: Construction and Decommissioning – Disturbance for the SPA population, razorbills are considered to have a moderate sensitivity to such sources of direct disturbance at sea (Garthe and Hüppop 2004, Furness et al., 2013).
2189. The maximum design scenario is for up to 3,393 vessel round trips per year over the operational lifetime of the project. Vessel types which will be required during the operation and maintenance phase include those used during routine inspections, repairs and replacement of equipment, major component replacement, painting or other coatings, removal of marine growth, replacement of access ladders, and geophysical surveys (Table 4.1).
2190. Based on information presented in the section on Project Alone: Operation and Maintenance – Disturbance for the St Abb’s Head to Fast Castle SPA kittiwake population and in the Offshore EIA Report, volume 2, chapter 13, baseline levels of vessel traffic in the Offshore Ornithology study area are relatively high. In the context of the baseline levels of vessel traffic across the Offshore Ornithology study area, the increase during the operation and maintenance phase is considered to be relatively small. Vessel movements will be within the Proposed Development array area and export cable corridor and will follow existing shipping routes to/from ports. In addition, Project Codes of Conduct included as a part of the NSVMP (Offshore EIA Report, volume 4, appendix 25) will be issued to all project vessel operators to avoid sudden changes in course or speed which will minimise the potential for disturbance. Within the Proposed Development array area, movements and associated maintenance activities will be restricted to individual wind turbines over a period of days to weeks.
2191. The size and noise outputs from vessels during the operation and maintenance phase will be similar to those used in the construction phase. However, the number of vessel return trips per year and their frequency will be much lower for the operation and maintenance phase compared to the construction phase. In addition, activities during the operation and maintenance phase will not occur simultaneously across the entirety of the Proposed Development array area and export cable corridor but intermittently within discrete (often very small) parts of these wider areas.
2192. Given the discrete areas relative to the species’ foraging range that will be subject intermittently to potential disturbance from vessel use and maintenance activities (Woodward et al., 2019), and the fact that these potential effects will be reduced compared to the construction and decommissioning phases, it is considered that there is no potential for disturbance during operation and maintenance to lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population.

Displacement/barrier effects

2193. As outlined above, displacement effects on the Troup, Pennan and Lion’s Head SPA razorbill population are estimated using the SNCB matrix approach, as applied to the Proposed Development array and two kilometre buffer (SNCBs 2022, Offshore EIA Report, volume 3, appendix 11.4). Thus, throughout this section, mortality from displacement is assumed to refer to that which results from both displacement and barrier effects. The approach used to derive predicted levels of mortality is as described in the section on Project Alone: Operation and Maintenance – Displacement/Barrier Effects for the St Abb’s Head to Fast Castle SPA kittiwake population above (and in the Offshore EIA Report, volume 3, appendix 11.4).
2194. On the basis of the advice provided in the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report), displacement effects on razorbill are estimated for the breeding and non-breeding periods. The displacement and associated mortality rates advised in the Scoping Opinion (subsequently termed the Scoping Approach) for razorbill are:

• Breeding period: 60% displacement with lower and upper mortality rates of 3% and 5%.
• Non-breeding period: 60% displacement with lower and upper mortality rates of 1% and 3%.
  2195. As with other species for which displacement effects are assessed (see above), the approach to estimating razorbill displacement effects advocated by the Scoping Opinion was considered overly precautionary in relation to both the displacement and mortality rates that were proposed, with these rates being higher than is considered to be justified on the basis of the available evidence (even when allowing for the incorporation of precaution in the assessment - volume 3, appendix 11.4, annex G of the Offshore EIA Report). Furthermore, the mortality rates advocated by the Scoping Opinion represented a marked change from the assumptions applied in assessments for other recent Scottish offshore wind farms (Marine Scotland 2017a,b,c) with no clear evidence apparently being available to justify such a change.
  2196. Based upon a consideration of the available evidence for razorbill displacement, the potential consequent mortality, previous precedent and a need to incorporate precaution within the assessment, an alternative Developer Approach to estimating displacement effects was determined (volume 3, appendix 11.4, annex G of the Offshore EIA Report). The rates adopted by the Developer Approach are:
• Breeding period: 50% displacement with a mortality rate of 1%.
• Non-breeding period: 50% displacement with a mortality rate of 1%.
  2197. Estimates of razorbill mortality were produced using the SNCB matrix on the basis of both the Scoping Approach and the Developer Approach (Offshore EIA Report, volume 3, appendix 11.4), with these estimates then apportioned to the Troup, Pennan and Lion’s Head SPA razorbill population during the breeding and non-breeding periods according to the MS Apportioning Tool (Butler et al. 2020) and the BDMPS approach (Furness 2015), respectively (Offshore EIA Report, volume 3, appendix 11.5, Table 5.159). The resulting mortality estimates for the breeding period were apportioned to age classes on the basis of the asymptotic age distribution of the population model used for the Troup, Pennan and Lion’s Head SPA razorbill PVAs in this assessment (Offshore EIA Report, volume 3, appendix 11.6). Based on advice provided by NatureScot and Marine Scotland Science following Roadmap Meeting 4 (G. Holland, email 26/01/2022), it was also assumed that 7% of the breeding adults in the SPA population miss breeding in any given year (i.e. sabbatical birds) so that the number of estimated adult deaths during the breeding season was adjusted accordingly.

Table 5.159: The Mean Peak Abundance Estimates of Razorbill in the Proposed Development Array Area and 2 km Buffer for each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be from the Troup, Pennan and Lion’s Head SPA Population in each Period. The proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented

2198. Based upon the estimates and assumptions detailed above, the potential annual mortality amongst the SPA razorbill population as a result of displacement is estimated as 1.4 adult and one immature birds based on the lower mortality rates for the Scoping Approach (i.e. Scoping Approach A) and as approximately three adult and two immature birds based upon the higher mortality rates for the Scoping Approach (i.e. Scoping Approach B) (Table 5.160). These effects are relatively evenly split between the breeding and non-breeding periods (Table 5.160).
2199. The annual mortality from displacement as determined using the Developer Approach is predicted to approximate to a single individual (adults and immatures combined, equating to 50% and 22% of the mortality predicted for the lower and upper range of the Scoping Approach, respectively (Table 5.160). The breeding season effects represent 33% of the total annual mortality, as determined by the Developer Approach.

Table 5.160: Estimated Potential Annual Mortality of Troup, Pennan and Lion’s Head SPA Razorbills as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach

2200. The additional annual mortality of adult razorbill from the Troup, Pennan and Lion’s Head SPA population predicted due to displacement from the Proposed Development array represents 0.01% of the current adult breeding population at this colony (i.e. 6,054 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach, and between approximately 0.02 – 0.05% of this population as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.090 – see Table 2.19 in the Offshore EIA Report, volume 3, appendix 11.6), the estimates of adult mortality equate to an increase of 0.1% for the Developer Approach and of 0.3 – 0.6% for the lower and upper estimates from the Scoping Approach.
2201. The potential levels of impact on the Troup, Pennan and Lion’s Head SPA razorbill population resulting from the mortality predicted from displacement and barrier effects associated with the Proposed Development array during the operation and maintenance phase are considered in more detail below in the Project Alone: Population-Level Impacts section. This presents the outputs from PVAs of the potential effects of predicted displacement mortality on the SPA population.

Changes to prey availability

2202. Potential impacts on key prey species for razorbills breeding at Troup, Pennan and Lion’s Head SPA during the operation and maintenance phase have been assessed in volume 2, chapter 9 of the Offshore EIA Report using the appropriate maximum design scenarios for these receptors. Reduction or disruption to prey availability through temporary and long-term subtidal habitat loss/disturbance, increased SSC and deposition, reductions in water clarity, EMF from subsea electrical cabling, and colonisation of subsea structures, could affect razorbill survival and productivity in the Troup, Pennan and Lion’s Head SPA population.
2203. The same evidence basis and context in relation to this effect pathway for the operation and maintenance phase applies to the Troup, Pennan and Lion’s Head SPA razorbill population as to the St Abb’s Head to Fast Castle SPA razorbill population. This is detailed in the section on Project Alone: Operation and Maintenance – Changes to Prey Availability for the St Abb’s Head to Fast Castle SPA population.
2204. Given this, it is considered that there is relatively little potential for the Troup, Pennan and Lion’s Head SPA razorbill population to be affected by changes to prey availability during the operation and maintenance phase, with any such effects being largely intermittent across a relatively small spatial extent. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population.

Project alone: population-level impacts

2205. As determined above, the effects from the Proposed Development alone which could lead to an adverse effect on the Troup, Pennan and Lion’s Head SPA razorbill population are limited to displacement (inclusive of barrier effects) during the operation and maintenance phase. For other effect pathways, there is considered to be no potential for an adverse effect on this population as a result of the Proposed Development alone, with any such effects likely to be small and of little, or no, consequence in terms of impacts at the population level.
2206. Given this, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the displacement effects associated with the Proposed Development, as determined by both the Scoping and Developer Approaches (see Table 5.160 above). The population model for the SPA population was a stochastic, density independent, matrix model, based upon the demographic parameters specified in Table 2.19 of the Offshore EIA Report, volume 3, appendix 11.6. The starting population size was the 2017 count for the SPA, with the projected population trends considered over a 35 year timescale (Offshore EIA Report, volume 3, appendix 11.5). The approach and methods to undertaking the PVA are as described in the section on Project Alone: Population-Level Impacts for the St Abb’s to Fast Castle SPA kittiwake population above (with further details provided in Offshore EIA Report, volume 3, appendix 11.6).
2207. Outputs from the PVA are summarised according to the median predicted population-sizes at the end of the projection period, and the three metrics which the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report) advised should be used for the interpretation of outputs and which have been shown to have relatively low sensitivity to factors such as varying population status and the mis-specification of the demographic rates underpinning the population model (Cook and Robinson 2015, Jitlal et al., 2017). These metrics are:

• The CPS – the median of the ratio of the end-point size of the impacted to un-impacted (or baseline) population, expressed as a proportion;
• The CPGR - the median of the ratio of the annual growth rate of the impacted to un-impacted population, expressed as a proportion; and
• The centile of the un-impacted population that matches the median (i.e. 50th centile) of the impacted population (based upon the distribution of the end-point population-sizes generated by the multiple replications of the model runs, the value should always be less than 50 because the median for the impacted population is not expected to exceed that for the un-impacted population).

Table 5.161: Projected 35 Year Population Sizes and Associated PVA Metrics for the Troup, Pennan and Lion’s Head SPA Razorbill Population Under Different Impact Scenarios for the Proposed Development Alone

2208. The PVA predicted that the Troup, Pennan and Lion’s Head SPA razorbill population would increase over the 35 year projection period irrespective of the effects from the Proposed Development. Thus, the population is predicted to be 64 – 68% larger than the current estimate of 6,054 adult birds under all scenarios, including the baseline which assumes no wind farm effects (Table 5.161). Although the predicted increases in population size are inevitably greatest for the baseline scenario (because the PVAs are based on density independent models, which assume all mortality from the wind farm effects is additive and that there are no compensatory mechanisms operating within the population), the differences with the impact scenarios are small. The predicted levels of increase are unlikely to occur in reality (and are, in part, a consequence of the absence of any compensatory density dependence within the models – as discussed in the section on Project Alone: Population-level impacts for the St Abb’s Head to Fast Castle SPA kittiwake population), whilst it is also notable that the predicted increase differs from the documented relative stability (albeit on the basis of sparse data) in the size of this SPA population over the last 15 years or so (see above).
2209. The predicted population-level impacts are small, irrespective of whether these are determined using the Developer or Scoping Approaches. Thus, for the higher mortality rates for the Scoping Approach (B), the CPS value indicates that the displacement effects from the Proposed Development alone would result in a reduction of 2% in the size of the SPA population after 35 years, relative to that in the absence of any wind farm effects (Table 5.161). The associated reduction in annual population growth rate (relative to that predicted under baseline conditions) is estimated to be 0.1%, whilst the centile value of 48.1 indicates a considerable overlap in the distributions of the predicted impacted and un-impacted population sizes and, hence, a high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years. As would be expected, the metrics as determined from either the lower mortality rates of the Scoping Approach or the Developer Approach suggest even smaller levels of impact (Table 5.161).
2210. For the same reasons as described in the section on Project-Alone: Population-Level Impacts for the St Abb’s Head to Fast Castle SPA razorbill population, the assessment of the Troup, Pennan and Lion’s Head SPA razorbill population incorporates high levels of precaution, which extend beyond the differences between the Developer and Scoping Approaches that are outlined above (and detailed in the Offshore EIA Report, volume 3, appendix 11.4). Notably, the concerns over the extent to which the seasonal mean peak abundances (which provide the basis for the displacement mortality estimates) are likely to be representative of the overall usage of the Proposed Development array and two kilometre buffer by razorbill are equally relevant to the Troup, Pennan and Lion’s Head SPA population as to the St Abb’s Head to Fast Castle SPA population. The evidence available from tracking data suggests that levels of usage of the Proposed Development array area and two kilometre buffer during the breeding season by razorbills from the Troup, Pennan and Lion’s Head SPA are likely to be low (Cleasby et al. 2018).

Project alone: conclusion

2211. It is considered that the predicted levels of impact from the Proposed Development alone on the Troup, Pennan and Lion’s Head SPA razorbill population are of a small scale, as determined by both the Developer and Scoping Approaches. For both the Developer and Scoping Approaches it is also the case that the centile metric indicates a high likelihood of the impacted population being of similar size to the un-impacted population after 35 years. These levels of impact are within the context of an assessment which incorporates high levels of precaution (particularly as determined by the Scoping Approach). Given this, it is concluded that the effects from the Proposed Development alone (as determined by either the Developer or Scoping Approaches) would not result in an adverse effect on this SPA population.

Effects in-combination

Effects of relevance to the in-combination assessment

2212. As detailed above, any effects from the Proposed Development alone on the Troup, Pennan and Lion’s Head SPA razorbill population during construction and decommissioning and resulting from disturbance and changes to prey availability during operation and maintenance will be small and highly localised. As such, there is considered to be no potential for these effect pathways to add to impacts at the population-level that might result from other effects pathways associated with the Proposed Development or from the effects due to other plans and projects.
2213. Therefore, the potential for effects of the Proposed Development to act on the Troup, Pennan and Lion’s Head SPA razorbill population in-combination with other plans and projects is limited to the displacement (inclusive of barrier effects) effect pathway during operation and maintenance. The following sections consider these potential effects for the Proposed Development in-combination with the other UK North Sea wind farms.

Displacement/barrier effects – operation and maintenance

2214. As described in Offshore EIA Report annex A of volume 3, appendix 11.6, estimates of breeding season displacement mortality which had been attributed to the Troup, Pennan and Lion’s Head SPA razorbill population were extracted from the existing assessments for offshore wind farms that are in planning, consented, under construction or in operation. As for the potential displacement mortality estimated for the Proposed Development, the mortality attributed to the SPA population from other offshore wind farms was estimated using the SNCB matrix approach, with details on the displacement and mortality rates that had been applied being available in each case. Thus, it was possible to adjust the estimated mortalities from each of the other projects to align with the displacement and mortality rates on which the Scoping and Developer Approaches are based.
2215. For the non-breeding periods, razorbill numbers associated with other offshore wind farms that are in planning, consented, under construction or in operation were extracted for each of the relevant seasonal periods from the cumulative totals collated for the East Anglia TWO and East Anglia ONE North submissions (MacArthur Green and Royal HaskoningDHV 2021, see Offshore EIA Report, annex E of volume 3, appendix 11.6 for more details). The cumulative numbers for each of the non-breeding periods were apportioned to the Troup, Pennan and Lion’s Head SPA razorbill population according to the BDMPS approach (Furness 2015), with the subsequent displacement mortality calculated according to the displacement and mortality rates appropriate to each of the Scoping and Developer Approaches (Table 5.160).

Table 5.162: Estimated Annual Mortality of Troup, Pennan and Lion’s Head SPA Razorbills as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, In-Combination with the other UK North Sea Wind Farms

2216. Incorporating the potential mortality predicted from the displacement effects associated with the other UK North Sea wind farms leads to a four to fivefold increase in the predicted displacement mortality compared to the Proposed Development alone for each of the Developer and Scoping Approaches (Tables 5.160 and 5.162). The non-breeding periods account for the majority (i.e. approximately 70 – 85%) of the predicted annual mortality for the Proposed Development in-combination with the other UK North Sea wind farms (with this contribution being highest for the Developer Approach and least for the upper range of the Scoping Approach – Table 5.162).
2217. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult razorbills from the Troup, Pennan and Lion’s Head SPA population predicted due to displacement represents between 0.07% of the current adult breeding population at this colony (i.e. 6,054 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach, and between 0.09 – 0.26% as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (based on applying a mortality rate of 0.090 – see Table 2.19 in the Offshore EIA Report, volume 3, appendix 11.6), the estimates of adult displacement mortality equate to an increase of 0.7% for the Developer Approach and of 1.1 – 2.9% for the lower and upper estimates from the Scoping Approach.
2218. The potential levels of impact on the Troup, Pennan and Lion’s Head SPA razorbill population resulting from the predicted mortality from displacement and barrier effects associated with the Proposed Development in-combination with the other wind farms in the UK North Sea during the operation and maintenance phase are considered in more detail below in the Effects In-Combination: Population-Level Impacts section. This presents the outputs from PVAs of the potential effects of predicted displacement mortality on the SPA population.

In-combination: population-level impacts

2219. As for the Proposed Development alone, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the displacement effects associated with the Proposed Development in-combination with the other UK North Sea wind farms. This was on the basis of the potential mortality as determined by both the Scoping and Developer Approaches (see Table 5.162 above).
2220. The approach to the PVA and the metrics used to summarise the PVA outputs are as described for the Proposed Development alone (see Project Alone: Population-Level Impacts section above).

Table 5.163: Projected 35 Year Population Sizes and Associated PVA Metrics for the Troup, Pennan and Lion’s Head SPA Razorbill Population Under Different Impact Scenarios for the Proposed Development In-Combination with the other UK North Sea Wind Farms

2221. Given that the in-combination effects are inevitably greater than those for the Proposed Development alone, the PVA metrics for the Proposed Development in-combination with the other UK North Sea wind farms suggest greater population-level impacts than as predicted for the Proposed Development alone (compare Table 5.163 with Table 5.161). However, overall, the predicted levels of impact remain relatively small.
2222. The CPS value for the Developer Approach indicates that the in-combination displacement effects would result in a reduction of less than 3% in the size of the SPA population after 35 years, relative to that in the absence of any wind farm effects, whilst for the Scoping Approach the CPS values indicate reductions of 4 – 10% after 35 years, relative to that in the absence of any wind farm effects (Table 5.163). The associated reduction in annual population growth rate (relative to that predicted under baseline conditions) is 0.1% for the Developer Approach and 0.1 – 0.3% for the Scoping Approach. The centile values of 41.1 (for the higher mortality rates of the Scoping Approach) to 47.8 (for the Developer Approach) indicate considerable overlap in the distributions of the predicted impacted and un-impacted population sizes and, hence, at least a reasonably high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years (Table 5.163).

In-Combination: Conclusion

2223. It is considered that the predicted levels of impact from the Proposed Development in-combination with the other UK North Sea wind farms on the Troup, Pennan and Lion’s Head SPA razorbill population are of a relatively small scale, as determined by both the Developer and Scoping Approaches. For both the Developer and Scoping Approaches it is also the case that the centile metric indicates at least a reasonably high likelihood of the impacted population being of similar size to the un-impacted population after 35 years. Furthermore, in relation to the Scoping Approach the predicted levels of impact should be considered within the context of the overly precautionary displacement and mortality rates used (volume 3, appendix 11.4, annex G of the Offshore EIA Report).
2224. Given this, it is concluded that the effects from the Proposed Development in-combination with the other UK North Sea wind farms would not result in an adverse effect on this SPA population. This conclusion applies to both the Scoping and Developer Approaches.

Assessment for the Breeding Seabird Assemblage

2225. The breeding seabird assemblage for the Troup, Pennan and Lion’s Head SPA is a qualifying feature on the basis of the SPA supporting in excess of 20,000 individual seabirds (with the citation also noting that the SPA supported approximately 150,000 individual seabirds of nine species in 1995). Razorbill is one of the species identified in the citation as contributing to the Troup, Pennan and Lion’s Head SPA breeding seabird assemblage, whilst kittiwake and guillemot are qualifying features in their own right.
2226. Potential impacts of the Proposed Development alone and in-combination with the other UK North Sea wind farms on the breeding seabird assemblage for the SPA could arise via effects on the individual species within the assemblage feature. For the Proposed Development alone, no potential for an adverse effect is identified in relation to the SPA populations of kittiwake, guillemot or razorbill, as determined by either the Developer or Scoping Approaches. For the Proposed Development in-combination with the other UK North Sea wind farms this is also the case for guillemot and razorbill. However, for the in-combination scenario the potential for an adverse effect is identified in relation to the SPA kittiwake population, as determined by the Scoping Approach (but not as determined by the Developer Approach).
2227. The Troup, Pennan and Lion’s Head SPA is currently two to (almost) two and half times larger than those at the St Abb’s Head to Fast Castle SPA and at the Forth Islands SPA. Therefore, despite the documented long-term decline in this population, it is not considered that the effects from the Proposed Development in-combination with the other UK North Sea wind farms (as determined by the Scoping Approach) are likely to lead to a risk of this population being lost from the breeding seabird assemblage at the Troup, Pennan and Lion’s Head SPA (in contrast to the conclusions reached for the St Abb’s Head to Fast Castle SPA and Forth Islands SPA). Also, given the range of species present within the SPA seabird assemblage and their relative abundances, together with the predicted level of impact on the SPA kittiwake population, it is considered that this potential adverse effect on the SPA kittiwake population would not be sufficient to result in a subsequent adverse effect on the seabird assemblage.
2228. Therefore, it is concluded that there is no potential for an adverse effect on the breeding seabird assemblage feature of the Troup, Pennan and Lion’s Head SPA either as a result of the effects from the Proposed Development alone or in-combination with other plans and projects. This conclusion is irrespective of whether the effects are determined by the Scoping or Developer Approach.

Site conclusion

Developer approach

2229. It is concluded that there is no potential for an adverse effect on the qualifying features of the Troup, Pennan and Lion’s Head SPA or on the named component species of the breeding seabird assemblage qualifying feature due to the effects from the Proposed Development alone or in-combination with other plans and projects. Consequently, it is concluded that there is no potential for an Adverse Effects on Integrity of the Troup, Pennan and Lion’s Head SPA.

Scoping approach

2230. It is concluded that the possibility of an adverse effect cannot be excluded for the Troup, Pennan and Lion’s Head SPA breeding kittiwake population. For the kittiwake population, the potential for an adverse effect arises from the Proposed Development in-combination with the other UK North Sea wind farms but not from the Proposed Development alone. The predicted impacts on the SPA kittiwake qualifying feature are not considered to be sufficient to lead to a potential adverse effect on the breeding seabird assemblage feature.
2231. Consequently, it is concluded that an Adverse Effects on Integrity of the Troup, Pennan and Lion’s Head SPA cannot be excluded due to effects of the Proposed Development in-combination with the other UK North Sea wind farms.

5.7.7.    East Caithness Cliffs SPA

European Site Information and Conservation Objectives

2232. East Caithness Cliffs SPA includes most of the sea-cliff areas between Wick and Helmsdale on the north-east coast of the Scottish mainland. The SPA is located approximately 274 km from the Proposed Development. The boundary of the SPA overlaps either partly or wholly with Castle of Old Wick to Craig Hammel SSSI, Craig Hammel to Sgaps Geo SSSI, Dunbeath to Sgaps Geo SSSI, Berriedale Cliffs SSSI, Ousdale Burn SSSI and Helmsdale Coast SSSI. The SPA was classified in 1996, with a marine extension classified in 2009. The seaward extension extends approximately 2 km into the marine environment.

2233. The site qualifies under Article 4.2 by regularly supporting five migratory seabird species and in excess of 20,000 breeding seabirds, including eight named component species ( Table 5.164   Open ▸ ). The potential for LSE has been identified in relation to three of the nine qualifying features ( Table 5.164   Open ▸ ), with the effect pathways associated with LSE for each of these detailed in Table 3.1   Open ▸ and set out in the assessment below.
2234. The Conservation Objectives of this SPA (as determined from NatureScot’s SiteLink (SiteLink (nature.scot)) are:

To avoid deterioration of the habitats of the qualifying species (listed below) or significant disturbance to the qualifying species, thus ensuring that the integrity of the site is maintained; and

To ensure for the qualifying species that the following are maintained in the long term:

• Population of the species as a viable component of the site
• Distribution of the species within site
• Distribution and extent of habitats supporting the species
• Structure, function and supporting processes of habitats supporting the species
• No significant disturbance of the species

2235. Further information on this European site is presented in Appendix A.

Table 5.164: Details on the qualifying features of the East Caithness Cliffs SPA

*Named components of the assemblage only.

Assessment for the Kittiwake Population

2236. The East Caithness Cliffs SPA kittiwake population is currently estimated to number 24,460 breeding pairs based upon the most recently available count data from 2015 (Offshore EIA Report, volume 3, appendix 11.5; Swann 2016), representing a 39.5% decline since it was last counted in 1999 (when the population was estimated to be 40,450 breeding pairs; Swann 2016).

The Potential for Impacts on the Kittiwake Population

2237. The Proposed Development and two kilometre buffer around the Proposed Development array area7 do not overlap with the East Caithness Cliffs SPA, so that potential impacts on its kittiwake population will only arise as a result of individuals from the colony occurring in the area (or vicinity) of the Proposed Development. Consequently, the main focus of the assessment for this SPA population is concerned with the Conservation Objective to maintain, in the long term, the population of the species as a viable component of the site, because the other Conservation Objectives either apply to the site itself, and not to areas beyond the boundary, or are encompassed by the assessment of this first Conservation Objective (as for the maintain in the long term no significant disturbance of the species, because disturbance would only be considered significant if it caused an adverse effect on the population viability of the qualifying features).
2238. From published information on kittiwake foraging ranges generally (Woodward et al., 2019) and inference from tracking data (Wakefield et al., 2017), it is apparent that during the breeding period, a relatively small proportion of kittiwakes from the East Caithness Cliffs SPA may occur within the area of the Proposed Development and two kilometre buffer. This is reflected in the findings of the apportioning exercise, which estimates that approximately 0.1% of the kittiwakes occurring on the Proposed Development array area during the breeding season derive from this SPA colony (Offshore EIA Report, volume 3, appendix 11.5). The breeding period for kittiwake is defined as mid-April to August, following the NatureScot (2020) guidance.
2239. During the non-breeding season there is likely to be the potential for kittiwake from the East Caithness Cliffs SPA to pass through offshore wind farms in the North Sea during the autumn and spring passage periods (defined as September to December and January to mid-April, respectively, on the basis of applying the BDMPS defined periods within the context of the overall non-breeding period defined by NatureScot; Furness 2015, NatureScot 2020, Offshore EIA Report, volume 3, appendix 11.5). Given the above, the Proposed Development may have potential effects on the East Caithness Cliffs SPA kittiwake population during breeding and non-breeding periods.

Project Alone: Construction and Decommissioning

Disturbance

2240. Direct disturbance to kittiwakes during the assumed eight-year construction phase may arise within the Proposed Development as a result of increased vessel movements, as well as from other activities directly associated with the installation of the turbine foundations and other infrastructure (see Table 4.1).
2241. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
2242. The total area to be affected by such disturbance over the assumed eight years of the construction phase represents a small proportion of the total area of marine habitat available to kittiwakes from the East Caithness Cliffs SPA. The Proposed Development array area encompasses 1,010 km2, whilst the Proposed Development offshore export cable encompasses 168 km2. Together these areas represent less than 1% of the total breeding season foraging area that is potentially available to the SPA kittiwake population, as defined by the generic measure of the species’ mean maximum breeding season foraging range plus 1 SD (i.e.156.1±144.5 km - Woodward et al., 2019), and assuming that this range is represented by a semicircle to the (main) seaward side of the colony. The Proposed Development is beyond the breeding season foraging area of kittiwakes from the East Caithness Cliffs SPA if considering the mean maximum foraging range only.
2243. During the non-breeding periods, kittiwake distribution is not constrained by the location of the breeding colonies and birds from the SPA population are likely to occur across large expanses of oceanic and maritime waters (Frederiksen et al., 2012, Furness 2015) and the potential for effects of construction-related disturbance is lower than during the breeding season.
2244. In addition, it is important to consider that the construction activities will not occur simultaneously across the entirety of the Proposed Development array area and offshore export cable corridor but, rather, will be carried out in different areas at different times. Thus, the activities will be concentrated within discrete (often small) parts of these wider areas, and within such areas they will not extend over the full duration of the construction phase, so further reducing the potential to which birds may be subject to disturbance effects.
2245. Given the low sensitivity of kittiwake to disturbance effects at sea (Garthe and Hüppop 2004, Furness et al., 2013), and the relatively small areas that will be subject to activities with the potential to result in intermittent, temporary disturbance, it is considered that there is no potential for construction or decommissioning related disturbance to lead to an adverse effect on the East Caithness Cliffs SPA kittiwake population. This conclusion is consistent with the outcome of the EIA which ‘screened’ out kittiwake as a species for which detailed consideration of the effects of construction disturbance was required (Offshore EIA Report, volume 2, chapter 11).

Displacement

2246. As detailed above, kittiwake is considered to have a low sensitivity to disturbance, whilst potential effects of disturbance during the construction and decommissioning phases will only extend across a very small part of the wider foraging areas used by the East Caithness Cliffs SPA kittiwake population and be limited to, at most, an eight year period during construction (and a likely similar or shorter period during decommissioning). Furthermore, as detailed above, potential effects of disturbance will not occur simultaneously across the entirety of the Proposed Development array area and offshore export cable corridor but, rather, will be carried out in different areas at different times. Thus, at any given time the potential for disturbance effects that could lead to displacement of kittiwakes from this SPA will be limited to relatively small areas, with the potential effects also being of a temporary nature.
2247. Therefore, based upon the above, it is considered that there is relatively little potential for the East Caithness Cliffs SPA kittiwake population to be affected by displacement during the construction or decommissioning phases. Consequently, it is considered that there is no potential for construction or decommissioning related displacement to lead to an adverse effect on the East Caithness Cliffs SPA kittiwake population. This conclusion is consistent with the outcome of the EIA which ‘screened’ out kittiwake as a species for which detailed consideration of the effects of construction-related displacement was required (Offshore EIA Report, volume 2, chapter 11).

Changes to Prey Availability 

2248. Key prey species for kittiwakes include sandeel and sprat (del Hoyo et al., 1996). Indirect effects on kittiwakes may arise as a result of changes in the availability, distribution, or abundance of these species during the construction and decommissioning phases of the Proposed Development. Reduction or disruption to prey availability may cause displacement from foraging grounds or reduced energy intake, affecting survival rates or productivity in the East Caithness Cliffs SPA kittiwake population in the short-term.
2249. During construction and decommissioning there are a number of ways in which effects on key prey species of seabirds may occur, which are outlined in the section on Project Alone: Construction and Decommissioning – Changes to Prey Availability for the St Abb’s Head to Fast Castle SPA kittiwake population. The same evidence base and context applies to the East Caithness Cliffs SPA kittiwake population as to the St Abb’s Head to Fast Castle SPA population in relation to the potential for such effects to lead to impacts on the population.
2250. Given this, it is considered that there is relatively little potential for the East Caithness Cliffs SPA kittiwake population to be affected by changes to prey availability during the construction and decommissioning phases, with any such effects being largely intermittent across a relatively small spatial extent, with most effects temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the East Caithness Cliffs SPA kittiwake population.