Project alone: conclusion
  1. The potential effects from the Proposed Development alone due to mortality from displacement, barrier effects and collisions during the operation and maintenance phase are predicted to have the potential to result in sizeable reductions in the size of the St Abb’s Head to Fast Castle SPA kittiwake population relative to the population size in the absence of these effects. Although it is considered likely that the assessment is overly precautionary, the level of the predicted impact is such that there is considered to be the potential for an adverse effect on the St Abb’s Head to Fast Castle SPA kittiwake population as a result of the Proposed Development alone. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.
Effects in-combination
Effects of relevance to the in-combination assessment
  1. As detailed above, any effects from the Proposed Development alone on the St Abb’s Head to Fast Castle SPA kittiwake 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.
  2. Therefore, the potential for effects of the Proposed Development to act on the St Abb’s Head to Fast Castle SPA kittiwake population in-combination with other plans and projects is limited to the displacement (inclusive of barrier effects) and collision risk effect pathways during operation and maintenance. Following advice from NatureScot provided through the Ornithology Roadmap process (at meeting 3, 8th December 2021), the following sections consider these potential effects for two in-combination scenarios, i.e. (i) the Proposed Development in-combination with the other Forth and Tay offshore wind farms and (ii) the Proposed Development in-combination with the offshore wind farms in the UK North Sea (noting that scenario (ii) includes those plans and projects which comprise scenario (i)).
Displacement/barrier effects – operation and maintenance
  1. As described in volume 3, appendix 11.6, annex E of the Offshore EIA Report, estimates of breeding season displacement mortality which had been attributed to the St Abb’s Head to Fast Castle SPA kittiwake 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 (Table 5.20), 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.
  2. Few estimates of displacement mortality are available from other projects for kittiwake (for any SPA population) during the non-breeding periods because such effects have not been considered important in most previous assessments for offshore wind farms in Scotland or England. Therefore, to derive the in-combination estimates, the relevant seasonal mean peak abundance estimates of kittiwake were extracted from the baseline data from the assessments for other projects in the UK North Sea waters (volume 3, appendix 11.6, annex E of the Offshore EIA Report). The displacement and mortality rates used for the Scoping and Developer Approaches (Table 5.20) were then applied to these estimates to obtain the overall potential kittiwake mortality, with this mortality then apportioned to the adult and immature age classes from the St Abb’s Head to Fast Castle SPA population according to the BDMPS approach (Furness 2015). As agreed through the Ornithology Roadmap process (at meeting 6, 10th May 2022), and as detailed in volume 3, appendix 11.6, annex E of the Offshore EIA Report), estimates are derived for projects within the larger North Sea development zones only due to the difficulty of locating the required information. Also, for some projects the baseline data were not presented in a format that allowed calculation of the seasonal mean peak abundance, so that alternative abundance estimates had to be used.
  3. The potential mortality estimates derived for the other projects were combined with those for the Proposed Development to give in-combination estimates for both the Forth and Tay wind farm scenario and the UK North Sea wind farm scenario, according to both the Scoping Approach and Developer Approach (Table 5.23).

 

Table 5.23:
Estimated Annual Mortality of St. Abb's Head to Fast Castle SPA Kittiwakes 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 Forth And Tay Wind Farms and UK North Sea Wind Farms

Table 5.23 Estimated Annual Mortality of St. Abb's Head to Fast Castle SPA Kittiwakes 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 Forth And Tay Wind Farms and UK North Sea Wind Farms

 

  1. The potential mortality resulting from the predicted displacement effects associated with other plans and projects is small relative to that predicted for the Proposed Development alone (Tables 5.20 and 5.23). Thus, inclusion of the other Forth and Tay wind farms increases the predicted displacement mortality of adult birds by approximately 10.5% and 11.5% compared to the Proposed Development alone for the Developer and Scoping Approaches, respectively. Considering the Proposed Development in-combination with the other UK North Sea wind farms increases the predicted displacement mortality by approximately 16% compared to the Proposed Development alone for the Scoping Approach but adds no further mortality compared to the in-combination with the Forth and Tay wind farms for the Developer Approach (because the Developer Approach does not attribute mortality to displacement during the non-breeding periods and breeding season effects on the SPA population are limited to the Proposed Development and the other Forth and Tay wind farms – see volume 3, appendix 11.6, annex E of the Offshore EIA Report).
  2. For the Proposed Development in-combination with the other Forth and Tay wind farms, the additional annual mortality of adult kittiwakes from the St Abb’s Head to Fast Castle SPA population predicted due to displacement represents 0.6% of the current adult breeding population at this colony (i.e. 10,904 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, and between approximately 0.3 – 0.9% 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 0.145 – see Table 2.13 in volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult displacement mortality equate to an increase of 4.0% for the Developer Approach and of 2.1 – 6.2% for the lower and upper estimates from the Scoping Approach.
  3. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult kittiwakes from the St Abb’s Head to Fast Castle SPA population predicted due to displacement represents between approximately 0.3 – 0.9% of the current adult breeding population at this colony 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, the estimates of adult displacement mortality equate to an increase of 2.2 – 6.5% for the lower and upper estimates from the Scoping Approach. The equivalent figures for the predicted additional mortality as determined by the Developer Approach are as for the Proposed Development in-combination with the other Forth and Tay wind farms.
  4. The potential levels of impact on the St Abb’s Head to Fast Castle SPA kittiwake population resulting from the mortality predicted from displacement and barrier effects associated with the Proposed Development in-combination with other wind farms in the Forth and Tay or in-combination with 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 combined effects of predicted displacement and collision mortality on the SPA population.
Collision risk - operation and maintenance
  1. As for displacement, breeding season collision estimates attributed to the St Abb’s Head to Fast Castle SPA kittiwake population were extracted from the existing assessments for offshore wind farms that are in planning, consented, under construction or in operation (volume 3, appendix 11.6, annex E of the Offshore EIA Report). Kittiwake collision estimates for the non-breeding periods were derived from the information collated in the East Anglia TWO and East Anglia ONE North submissions (MacArthur Green and Royal HaskoningDHV 2021), with the collision numbers for some projects updated using more recent design information where required (volume 3, appendix 11.6, annex E of the Offshore EIA Report). The non-breeding season collision estimates were apportioned to the St Abb’s Head to Fast Castle SPA population according to the BDMPS approach (Furness 2015).
  2. Collision estimates based on consented and ‘as-built’[11] designs were also considered but for the current SPA population this did not affect the collision estimates for the other Forth and Tay wind farms and had minimal effects on those for the other UK North Sea wind farms (with the respective totals differing by approximately one adult bird). Therefore, only the estimates for the consented designs are considered in this case.
  3. In contrast to the displacement estimates derived for the other projects, existing collision estimates for these projects were not adjusted to align with the Scoping Approach of using the maximum (rather than the mean) monthly estimate of the density of birds in flight (with all of the other projects likely to have followed the ‘standard’ approach of using the mean density). Such an adjustment would require the re-calculation of the CRMs for each project, which would not be feasible in many cases because of the difficulty in accessing the appropriate baseline data.
  4. As for displacement, the potential mortality estimates derived for the other projects were combined with those for the Proposed Development to give estimates for (i) the Proposed Development in-combination with the other Forth and Tay wind farms and (ii) the Proposed Development in-combination with the other UK North Sea wind farms according to both the Scoping Approach and Developer Approach (noting that for the Scoping Approach it is only the estimates for the Proposed Development that are calculated according to this approach) (Table 5.24).

 

Table 5.24:
Predicted Collision Effects on the St Abb’s Head to Fast Castle SPA Kittiwake Population Due to the Proposed Development In-Combination with Other Projects in The Forth And Tay and in UK North Sea Waters. Estimates are Presented for Both the Scoping Approach and Developer Approach

Table 5.24: Predicted Collision Effects on the St Abb’s Head to Fast Castle SPA Kittiwake Population Due to the Proposed Development In-Combination with Other Projects in The Forth And Tay and in UK North Sea Waters. Estimates are Presented for Both the Scoping Approach and Developer Approach

 

  1. As with the displacement effects, the potential mortality resulting from the predicted collision effects associated with other plans and projects is small relative to that predicted for the Proposed Development alone (Tables 5.21 and 5.24). Thus, inclusion of the other Forth and Tay wind farms increases the predicted collision mortality of adult birds by approximately 3.6% and 2.5% compared to the Proposed Development alone for the Developer and Scoping Approaches, respectively. Considering the Proposed Development in-combination with the other UK North Sea wind farms increases the predicted collision mortality by approximately 8.3% and 5.8% compared to the Proposed Development alone for the Developer and Scoping Approaches, respectively. As for the displacement effects, predicted collision effects to the SPA population during the breeding season are limited to the Proposed Development and the other Forth and Tay wind farms (see volume 3, appendix 11.6, annex E of the Offshore EIA Report).
  2. For the Proposed Development in-combination with the other Forth and Tay wind farms, the additional annual mortality of adult kittiwakes from the St Abb’s Head to Fast Castle SPA population predicted due to collisions represents 1.9% of the current adult breeding population at this colony (i.e. 10,904 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach, and 2.7% of this population as determined by 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 0.145 – see Table 2.13 in volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult collision mortality equate to an increase of 12.8% for the Developer Approach and of 18.4% for the Scoping Approach.
  3. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult kittiwakes from the St Abb’s Head to Fast Castle SPA population predicted due to collisions represents 1.9% of the current adult breeding population at this colony (i.e. 10,904 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, and 2.7% of this population as determined by 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 0.145 – see Table 2.13 in volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult collision mortality equate to an increase of 13.4% for the Developer Approach and of 18.9% for the Scoping Approach.
  4. The potential levels of impact on the St Abb’s Head to Fast Castle SPA kittiwake population resulting from the mortality predicted from collisions associated with the Proposed Development in-combination with other wind farms in the Forth and Tay or in-combination with 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 combined effects of predicted displacement and collision mortality on the SPA population.
In-Combination: Population-Level Impacts
  1. As for the Proposed Development alone, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the combined displacement and collision effects associated with the Proposed Development in-combination with the other Forth and Tay wind farms and 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 Tables 5.23 and 5.24 above).
  2. 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 5.25:
Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Kittiwake Population Under Different Impact Scenarios for the Proposed Development In-Combination With the Other Forth and Tay Wind Farms

Table 5.25   Open ▸ Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Kittiwake Population Under Different Impact Scenarios for the Proposed Development In-Combination With the Other Forth and Tay Wind Farms

 

Table 5.26:
Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head To Fast Castle SPA Kittiwake Population Under Different Impact Scenarios for the Proposed Development In-Combination With The Other UK North Sea Wind Farms

Table 5.26 Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head To Fast Castle SPA Kittiwake Population Under Different Impact Scenarios for the Proposed Development In-Combination With The Other UK North Sea Wind Farms

 

  1. As expected on the basis 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 either the other Forth and Tay wind farms or the other UK North Sea wind farms suggests more marked population-level impacts (Tables 5.25 and 5.26). Focussing on the outputs for the Proposed Development in-combination with the other UK North Sea wind farms, the CPS value for the Developer Approach indicates that the SPA population size would be reduced by approximately 50% relative to the predicted population size under baseline conditions after 35 years, whilst the equivalent reduction for the Scoping Approach is 59 – 66% (Table 5.26). Reductions in the annual population growth rate (relative to that predicted under baseline conditions) are estimated to be 2% on the basis of the Developer Approach and 2.4 – 2.9% on the basis of the Scoping Approach. On the basis of the Developer Approach, the centile value is estimated to be 7.6 after 35 years, whilst the equivalent values for the Scoping Approach are 1.3 – 3.5 (Table 5.26). Thus, the centile metric indicates very little overlap in the distribution of the predicted impacted and un-impacted population sizes, suggesting a high likelihood of the impacted population being smaller than the un-impacted population after 35 years, irrespective of whether the effects are estimated using the Developer or Scoping Approaches.
  2. The PVA metrics suggest slightly lower, but broadly similar, population-level impacts for the Proposed Development in-combination with the other Forth and Tay wind farms (as follows from the smaller level of predicted mortality associated with this in-combination scenario – Table 5.25).
  3. As detailed above in the Project Alone: Population-Level Impacts section, in considering the level of these potential impacts and their implications for the SPA population, it is important to take account of the fact that the SPA population is predicted to decline irrespective of the in-combination wind farm effects and that these effects are unlikely to be the critical factor determining the overall population trend and condition status of the feature. Also, for the reasons outlined above for the project alone, the in-combination assessment is likely to be highly precautionary but with a likelihood that this issue is compounded further via the summing of effects derived from multiple assessments which incorporate similarly high levels of precaution.
In-Combination: conclusion
  1. The potential effects from the Proposed Development in-combination with either the other Forth and Tay wind farms or the other UK North Sea wind farms are predicted to have the potential to result in marked reductions in the size of the St Abb’s Head to Fast Castle SPA kittiwake population relative to the population size in the absence of these effects. Although it is considered likely that the assessment is overly precautionary, the level of the predicted impact is such that there is considered to be the potential for an adverse effect on the St Abb’s Head to Fast Castle SPA kittiwake population as a result of the predicted in-combination effects. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.

Assessment for the herring gull population

  1. The St Abb’s Head to Fast Castle SPA herring gull population is currently estimated to number 306 breeding pairs, which is considerably lower than the citation population of 1,160 pairs (Figure 5.14). The whole SPA has only been counted sporadically since 1985, but the annual count data from the St Abb’s Head NNR (which have comprised the bulk of the SPA population in recent decades) demonstrate a long-term decline between 1986 and 2021. This decline has been relatively gradual, following a marked reduction in numbers in the late 1980s. The population size has been below the citation population size in all years for which count data are available since 1987 (Figure 5.14).

Figure 514:
Herring Gull Population Trend at the St Abb’s Head NNR Between 1986 and 2021, With Four Counts for the Entire St Abb’s Head to Fast Castle SPA Also Shown (Noting that the Latest SPA Count is Shown for 2018 Because it Spans The Period 2016 – 2020). The Red Line Shows The Citation Population Size for the SPA (1,160 Pairs). Data are from The Seabird Monitoring Programme Database (Seabird Monitoring Programme | JNCC (bto.org))

Figure 514:  Herring Gull Population Trend at the St Abb’s Head NNR Between 1986 and 2021, With Four Counts for the Entire St Abb’s Head to Fast Castle SPA Also Shown (Noting that the Latest SPA Count is Shown for 2018 Because it Spans The Period 2016 – 2020). The Red Line Shows The Citation Population Size for the SPA (1,160 Pairs). Data are from The Seabird Monitoring Programme Database (Seabird Monitoring Programme | JNCC (bto.org))

 

The potential for impacts on the herring gull population
  1. The Proposed Development and two kilometre buffer around the Proposed Development array area7 do not overlap with the St Abb’s Head to Fast Castle SPA, so that potential impacts on its herring gull 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 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).
  2. From published information on herring gull foraging ranges (Woodward et al. 2019), it is likely that during the breeding period herring gulls from the St Abb’s Head to Fast Castle 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 3% of the herring gulls 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 herring gull is defined as April to August, following NatureScot (2020).
  3. In the non-breeding season, herring gulls in Great Britain are largely sedentary with relatively short local movements only (Wernham et al. 2002). However, there is an influx of breeding birds of Scandinavian breeding subspecies, L. argentatus argentatus (Coulson et al., 1984). On this basis, and following the scoping advice from NatureScot (volume 3, appendix 6.2 of the Offshore EIA Report), it is assumed that during the non-breeding period herring gulls remain largely within the waters in the region of the breeding colony, as defined by the mean maximum foraging range plus 1 SD (Woodward et al. 2019, Offshore EIA Report, volume 3, appendix 11.5). To account for the influx of birds from other regions to this regional population during the non-breeding period, the regional non-breeding population is assumed to increase (relative to the size of the breeding population) in accordance with the proportion of continental and western UK birds estimated to be present in the UK North Sea and Channel BDMPS (Furness 2015, Offshore EIA Report, volume 3, appendix 11.5).
  4.  Given the above, there is potential for the Proposed Development to have effects on the St Abb’s Head to Fast Castle SPA herring gull population during both the breeding and non-breeding periods.
Project alone: construction and decommissioning
Changes to prey availability
  1. Herring gulls have a highly opportunistic diet (del Hoyo et al., 1996), utilising terrestrial, intertidal and marine habitats to forage for a wide variety of prey species including invertebrates, small fish and carrion (including fishery discards). Indirect effects on herring gulls 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 St. Abb’s Head to Fast Castle SPA herring gull population in the short-term.
  2. During construction there are a number of ways in which effects on herring gull prey species could occur, which are as outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the SPA kittiwake population. However, the total area within which prey could be affected represents a relatively small proportion of the total area of marine habitat available to herring gulls from the St Abb’s Head to Fast Castle SPA. The Proposed Development array area encompasses 1,010 km2, whilst the Proposed Development export cable corridor encompasses 168 km2. Together these areas represent c. 10% of the total breeding season marine foraging area that is potentially available to the SPA herring gull population, as defined by the species’ mean-maximum breeding season foraging range plus 1 SD (i.e. 58.8±26.8 km; Woodward et al., 2019) ) and assuming that this range is represented by a semicircle to the seaward side of the colony. Furthermore, given their flexible foraging habits and the distance between the Proposed Development and the SPA, it is likely that the area of marine habitat encompassed by the Proposed Development is not of key importance for herring gulls breeding at the St. Abb’s Head to Fast Castle SPA. Non-breeding season effects are expected to similar since herring gulls in Great Britain do not disperse widely during winter (Wernham et al. 2002).
  3. During decommissioning, the effects from changes in prey availability are considered to be the same (or less) as for construction. It is currently unclear as to how the presence, and subsequent removal of, subsea structures may affect herring gull prey species (Birchenough and Degrae 2020; Scott, 2022). It is possible that prey abundance could decline from the levels present during the operation and maintenance period. This could occur if the sub-surface structures associated with the Proposed Development in the marine environment lead to an increase in key prey abundance within the Proposed Development array area and export cable corridor via the provision of artificial reef habitats. However, some infrastructure (such as scour and cable protection) is assumed to be left in situ with the impact of colonisation of infrastructure continuing in perpetuity following decommissioning. Thus, any reduction in prey abundance through removal of foundations is likely to be very small relative to the area over which breeding and non-breeding herring gulls forage.
  4. Given their wide-ranging foraging behaviour and plasticity in foraging habitat and diet (del Hoyo et al., 1996), together with any effects being intermittent, spatially-restricted and temporary in nature, 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 St. Abb’s to Fast Castle SPA herring population. This conclusion is consistent with the outcome of the EIA which concluded that effects from changes in prey availability on herring gulls during construction and decommissioning were not significant in EIA terms (volume 2, chapter 11 of the Offshore EIA Report).
Project alone: operation and maintenance
Collision risk
  1. Predictions of the number of herring gulls at risk from collisions due to the Proposed Development were calculated using the deterministic version of the SOSS offshore collision risk model (Band 2012, volume 3, appendix 11.3 of the Offshore EIA Report). Following the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report), the assessment is based on the outputs from both options 2 and 3 of the CRM, which use the generic flight height data and for which option 2 assumes a uniform distribution of flight heights across the rotor swept zone and option 3 assumes the modelled flight height distribution (Band 2012, Johnston et al. 2014a,b). In accordance with the recommendations of the SNCBs (2014), and as advised by the Scoping Opinion, avoidance rates of 99.5% and 99.0% were applied to the outputs from option 2 and option 3, respectively.
  2. As outlined for kittiwake above, guidance on the use of the CRM suggests that model predictions should be based upon the mean monthly densities of flying birds estimated within the array area (Band 2012)8 and, to the best of the Applicant’s knowledge, this approach has been applied in all recent UK offshore wind farm assessments. Despite this, the Scoping Opinion advised that the CRMs for the Proposed Development should use the maximum monthly densities of flying birds within the array area. Further details on this are provided above in the Project Alone: Operation and Maintenance - Collision Risk section for kittiwake (and in volume 3, appendix 11.3 of the Offshore EIA Report) but, as a result of this overly precautionary approach (which does not follow previous precedent), the CRMs for herring gull were undertaken following:
  • The Scoping Approach of using the maximum monthly densities, and
  • The Developer Approach of using the mean monthly densities.
    1. In addition to the above, collision estimates for herring gulls were also calculated using options 2 and 3 of the stochastic version of the CRM (McGregor et al. 2018) with avoidance rates as derived from the bird collision-avoidance study undertaken at the Thanet offshore wind farm (Bowgen and Cook 2018). These additional collision estimates are not used as the basis of the assessments on the SPA herring gull populations but, instead, are used solely to illustrate the consequences of applying these alternative avoidance rates which have been derived from studies at an actual offshore wind farm. Details of these additional CRMs are provided in annex C of volume 3, appendix 11.3 of the Offshore EIA Report.
    2. Herring gull collision estimates are calculated for the breeding and non-breeding periods, with estimates apportioned to the St Abb’s Head to Fast Castle SPA population according to the NatureScot (2018) approach but with allowance made for the influx of birds from other regions during the non-breeding period (Offshore EIA Report, volume 3, appendix 11.5). The resulting estimates were apportioned to age classes according to the plumage characteristics of herring gulls recorded during the baseline surveys (EIA Report, volume 3, appendix 11.1), whilst on the basis of advice provided by NatureScot and Marine Scotland Science following Roadmap Meeting 4 (G. Holland, email 26/01/2022), it was also assumed that 35% of the breeding adults in the SPA population miss breeding in any given year (i.e. sabbatical birds) so that the number of adult collisions estimated during the breeding season was adjusted accordingly.
    3. Based upon option 2 of the deterministic CRM with a 99.5% avoidance rate applied, and in conjunction with the estimates and assumptions detailed above, the annual collision mortality of herring gulls from the St Abb’s Head to Fast Castle SPA is predicted to be approximately 0.8 adults and 0.1 immatures as determined by the Scoping Approach, and 0.5 adults and 0.1 immatures as determined by the Developer Approach (Table 5.27). The vast majority of this mortality (i.e. approximately 90% for adults and 70% for immatures) is predicted to occur during the breeding season. The collision estimates for option 3 of the deterministic CRM with a 99.0% avoidance rate applied (which was also recommended by the Scoping Opinion as a basis for the assessment) are not presented in Table 5.27 below but give outputs that are approximately 40% lower than the option 2 estimates for both the Scoping and Developer Approaches (Offshore EIA, volume 3, appendix 11.3). In addition, the collision estimates produced using options 2 and 3 of the stochastic CRM with the Bowgen and Cook (2018) avoidance rates applied were similar to those obtained from option 3 of the deterministic CRM with the SNCB recommended 99.0% avoidance rate, and hence also substantially lower than those presented in Table 5.27 below (see Offshore EIA report, volume 3, appendix 11.3, annex C).

 

Table 5.27:
Predicted Collision Effects from the Proposed Development on the St Abb’s Head to Fast Castle SPA Herring Gull Population, As Determined by The Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based On Options 2 and 3 of the Deterministic CRM Using 99.5% and 99.0% Avoidance Rates, Respectively (See Text)

Table 5.27 Predicted Collision Effects from the Proposed Development on the St Abb’s Head to Fast Castle SPA Herring Gull Population, As Determined by The Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based On Options 2 and 3 of the Deterministic CRM Using 99.5% and 99.0% Avoidance Rates, Respectively (See Text)

 

  1. Based upon the estimates from option 2 of the CRM, the additional annual mortality of adult herring gulls from the St Abb’s Head to Fast Castle SPA population predicted due to collisions with wind turbines in the Proposed Development Array represents approximately 0.07% of the number of adults currently estimated to breed at this colony (i.e. 612 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach and approximately 0.12% as determined by 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 0.122 – see Table 2.11 in volume 3, appendix 11.6 of the Offshore EIA Report), the predicted adult collision mortality equates to increases of 0.6% and 1.0% for the Developer and Scoping Approaches, respectively.
  2. The potential levels of impact on the St Abb’s Head to Fast Castle SPA herring gull population resulting from the predicted collision mortalities in Table 5.27 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 collision mortality on the SPA population.
Changes to prey availability
  1. Potential impacts on key prey species for herring gulls breeding at St. Abb’s Head to Fast Castle 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, EMF from subsea electrical cabling, and colonisation of subsea structures could affect herring gull survival and productivity in the St. Abb’s Head to Fast Castle SPA population.
  2. Artificial structures introduced to the marine environment provide hard substrate for settlement of various organisms, which can increase local food availability for higher trophic levels. Whilst there is mounting evidence of potential benefits of artificial structures in marine environment (Birchenough and Degrae 2020), the statistical significance of such benefits and details about trophic interactions remain largely unknown (Scott, 2022).
  3. Given their wide-ranging foraging behaviour and plasticity in foraging habitat and diet (del Hoyo et al., 1996), together with any effects on prey during operation and maintenance being largely intermittent across a relatively small spatial extent, 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 St. Abb’s to Fast Castle SPA herring gull population. This conclusion is consistent with the outcome of the EIA which concluded that effects from changes in prey availability on herring gulls during operation and maintenance were not significant in EIA terms (volume 2, chapter 11 of the Offshore EIA Report).
Project alone: population-level impacts
  1. As determined above, the effects from the Proposed Development alone which could lead to an adverse effect on the St Abb’s Head to Fast Castle SPA herring gull population are limited to collision mortality 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.
  2. Given this, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the collisions associated with the Proposed Development, as determined by both the Scoping and Developer Approaches (see Table 5.27 above). This was undertaken using the outputs from option 2 of the deterministic CRM with a 99.5% avoidance rate applied, as presented in Table 5.27 (noting that these are the more precautionary of the outputs from the different CRM approaches recommended by the Scoping Opinion). The population model for the SPA population was a stochastic, density independent, matrix model, based upon the demographic parameters specified in Table 2.11 of volume 3, appendix 11.6 of the Offshore EIA Report. The starting population size was the 2016 – 2020 count for the SPA, with the projected population trends considered over a 35 year timescale (volume 3, appendix 11.5 of the Offshore EIA Report). The approach and methods to undertaking the PVA are as described for kittiwake above (with further details provided in volume 3, appendix 11.6 of the Offshore EIA Report).
  3. 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:

 

Table 5.28:
Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Herring Gull Population Under Different Impact Scenarios for the Proposed Development Alone

Table 5.28: Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Herring Gull Population Under Different Impact Scenarios for the Proposed Development Alone

 

  1. The PVA predicted that the St Abb’s Head to Fast Castle SPA herring gull population would increase strongly over the 35 year projection period irrespective of the effects from the Proposed Development. Thus, the population is predicted to be 10 times larger than the current estimate of 612 adult birds under all scenarios, including the baseline which assumes no wind farm effects (Table 5.28). 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 two 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 trend does not reflect the documented long-term for this SPA population (Figure 5.14).
  2. The predicted population-level impacts are small, irrespective of whether these are determined using the Developer or Scoping Approaches. Thus, for the Scoping Approach the CPS value indicates that the collision mortality associated with the Proposed Development alone would result in a reduction of approximately 3% in the size of the SPA population after 35 years, relative to that in the absence of any wind farm effects (Table 5.28). 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 45.9 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 for the Developer Approach suggest even smaller levels of impact (Table 5.28). In addition, it should be noted that these predicted levels of impact are derived from the more precautionary of the two CRM approaches recommended by the Scoping Opinion, with the alternative approach giving collision estimates that were 40% lower than those used for the PVA.
Project alone: conclusion
  1. For both the Developer and Scoping Approaches, the potential effects from the Proposed Development alone on the St Abb’s Head to Fast Castle SPA herring gull population are predicted to be small, with the resultant population-level impacts also predicted to be small. In addition, the PVA metrics indicate a high chance of the population being of a similar size to that which would occur in the absence of the Proposed Development after 35 years. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.
Effects in-combination
Effects of relevance to the in-combination assessment
  1. As detailed above, any effects from the Proposed Development alone on the St Abb’s Head to Fast Castle SPA herring gull population during construction and decommissioning and resulting from 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.
  2. Therefore, the potential for effects of the Proposed Development to act on the St Abb’s Head to Fast Castle SPA herring gull population in-combination with other plans and projects is limited to the collision risk effect pathway during operation and maintenance. Following advice from NatureScot provided through the Ornithology Roadmap process (at meeting 3, 8th December 2021), the following sections consider these potential effects for (i) the Proposed Development in-combination with the other Forth and Tay wind farms and (ii) the Proposed Development in-combination with the other UK North Sea wind farms (noting that scenario (ii) includes those plans and projects which comprise scenario (i)).
Collision risk - operation and maintenance
  1. Breeding and non-breeding season collision estimates attributed to the St Abb’s Head to Fast Castle SPA herring gull population were extracted from the existing assessments for offshore wind farms that are in planning, consented, under construction or in operation (Offshore EIA, volume 3, appendix 11.6, annex D). As for the Proposed Development, the non-breeding season collision estimates for the other plans and projects were adjusted to account for the influx of birds from other regions to this regional population during the non-breeding period, in accordance with the estimates used for the UK North Sea and Channel BDMPS (see above, Offshore EIA Report, volume3, appendix 11.5, Furness 2015).
  2. The collision estimates derived for the other plans and projects were combined with those for the Proposed Development to give in-combination estimates for both the Forth and Tay wind farms and the UK North Sea wind farms according to both the Scoping Approach and Developer Approach. However, the potential effects on the SPA population were limited to the other Forth and Tay wind farms, noting that apportioning of the non-breeding season effects for herring gull assumed that birds remain within the waters in the region of the breeding colony (as described above, see also Offshore EIA Report, volume 3, appendix 11.5). Given that these two different in-combination scenarios are equivalent, the predicted effects are reported solely for the UK North Sea wind farms in the tables below (Table 5.29). Options based on consented and ‘as-built’[12] designs did not affect the collision estimates from the other plans and projects, so that estimates are reported for the consented designs only. The collision estimates used for the Proposed Development are those presented in Table 5.29, which derived from the more precautionary of the two different CRM approaches recommended by the Scoping Opinion (see above).
  3. The existing collision estimates for the other plans and projects were not adjusted to align with the Scoping Approach of using the maximum (rather than the mean) monthly estimate of the density of birds in flight (with all of the other projects included with the in-combination scenario having followed the ‘standard’ approach of using the mean density). As explained for kittiwake above, such an adjustment would require the re-calculation of the CRMs for each project, which would not be feasible in many cases because of the difficulty in accessing the appropriate baseline data. Thus, it is only the estimates for the Proposed Development which differentiate the Developer and Scoping Approaches for the in-combination scenarios that are presented below.

 

Table 5.29:
Predicted Collision Effects on the St Abb’s Head to Fast Castle SPA Herring Gull Population due to The Proposed Development In-Combination With Other Projects in the UK North Sea Waters. Estimates are Presented for Both The Scoping Approach and Developer Approach

Table 5.29: Predicted Collision Effects on the St Abb’s Head to Fast Castle SPA Herring Gull Population due to The Proposed Development In-Combination With Other Projects in the UK North Sea Waters. Estimates are Presented for Both The Scoping Approach and Developer Approach

1The Forth and Tay and UK North Sea in-combination effects for the SPA population are equivalent (so that they are reported for the latter scenario only).

 

  1. Incorporating the potential mortality resulting from the predicted collision effects associated with other plans and projects increases the predicted collision mortality of adult birds by 60% and 36% compared to the Proposed Development alone for the Developer and Scoping Approaches, respectively (Tables 5.27 and 5.29). As noted above, the predicted collision effects to the SPA population are limited to the Proposed Development and the other Forth and Tay wind farms (see Offshore EIA Report, volume 3, appendix 11.6, annex D), with the combined collision mortality predicted for the other Forth and Tay wind farms being lower than for the Proposed Development alone during the breeding season but higher than for Proposed Development alone during the non-breeding period.
  2. For the Proposed Development in-combination with these other wind farms, the additional annual mortality of adult herring gulls from the St Abb’s Head to Fast Castle SPA population predicted due to collisions represents 0.12% of the current adult breeding population at this colony (i.e. 612 individuals – Table 3.3 in volume 3, appendix 11.5 of the Offshore EIA Report) as determined by the Developer Approach, and 0.17% of this population as determined by 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 0.122 – see Table 2.11 in volume 3, appendix 11.6 of the Offshore EIA Report), the estimates of adult collision mortality equate to an increase of 1.0% for the Developer Approach and of 1.4% for the Scoping Approach.
  3. The potential levels of impact on the St Abb’s Head to Fast Castle SPA herring gull population resulting from the predicted collision mortalities in Table 5.29 are considered in more detail below in the In-Combination: Population-Level Impacts section. This presents the outputs from PVAs of the potential effects of predicted collision mortality on the SPA population.
In-combination: population-level impacts
  1. As for the Proposed Development alone, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the collision 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 5.29 above).
  2. 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 5.30:
Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Herring Gull Population Under Different Impact Scenarios for the Proposed Development In-Combination With the Other UK North Sea Wind Farms

Table 5.30: Projected 35 Year Population Sizes and Associated PVA Metrics for the St Abb’s Head to Fast Castle SPA Herring Gull Population Under Different Impact Scenarios for the Proposed Development In-Combination With the Other UK North Sea Wind Farms

 

  1. 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 5.28 with Table 5.30). However, the changes in the values of the PVA metrics are small, with the reduction in the size of the SPA population after 35 years relative to that in the absence of any wind farm effects predicted to be approximately 4% for the Scoping Approach (compared to 3% for the Proposed Development alone). The equivalent reduction is smaller for the metrics associated with the Developer Approach. For both the Developer and Scoping Approaches, the centile metric continues to indicate a high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years (Table 5.30).
  2. It is also the case that these predicted levels of impact are derived using the more precautionary of the two CRM approaches recommended by the Scoping Opinion for the Proposed Development (volume 3, appendix 6.2 of the Offshore EIA Report). Reliance on the alternative approach would likely reduce the predicted levels of impact considerably, given that it reduced the collision estimates for the Proposed Development by approximately 40% and that the collision effects for the Proposed Development comprise a substantial part of the overall in-combination effects.
In-combination: conclusion
  1. On the basis of the above considerations, it is concluded that the population-level impacts resulting from the Proposed Development in-combination with the other UK North Sea wind farms would not produce an adverse effect on the St Abb’s Head to Fast Castle SPA herring gull population. This conclusion applies irrespective of whether effects are determined according to the Scoping Approach or the Developer Approach.

Assessment for the guillemot population

  1. The St Abb’s Head to Fast Castle SPA guillemot population has shown an overall increase during the last 30 years or so, and relative stability since the late 1990s, based on count data from the St Abb’s Head NNR (which holds the vast majority of the SPA population – Figure 5.15). The population size has remained above the citation population size (31,750 individuals) since designation.


Figure 515:
Guillemot Population Trend at the St Abb’s Head NNR Between 1986 and 2018, With Two Counts for the Entire St Abb’s Head to Fast Castle SPA Also Shown (Noting That the Latest SPA Count Is Shown For 2017 Because It Spans The Period 2016 – 2018). The Red Line Shows The Citation Population Size For The SPA (31,750 Individuals) [13]. Data Are From The Seabird Monitoring Programme Database (Seabird Monitoring Programme | JNCC (bto.org))

Figure 515: Guillemot Population Trend at the St Abb’s Head NNR Between 1986 and 2018, With Two Counts for the Entire St Abb’s Head to Fast Castle SPA Also Shown (Noting That the Latest SPA Count Is Shown For 2017 Because It Spans The Period 2016 – 2018). The Red Line Shows The Citation Population Size For The SPA (31,750 Individuals) [13]. Data Are From The Seabird Monitoring Programme Database (Seabird Monitoring Programme | JNCC (bto.org))

The potential for impacts on the guillemot population
  1. The Proposed Development and two kilometre buffer around the Proposed Development array area7 do not overlap with the St Abb’s Head to Fast Castle SPA, so that potential impacts on its guillemot 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).
  2. From published information on guillemot foraging ranges generally (Woodward et al. 2019) and tracking from the SPA specifically (Wakefield et al. 2017), it is highly likely that during the breeding period guillemot from the St Abb’s Head to Fast Castle 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 42% of the guillemot 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 guillemot is defined as April to mid-August, following the NatureScot (2020) guidance.
  3. Based on the NatureScot scoping advice (volume 3, appendix 6.2 of the Offshore EIA Report) and subsequent correspondence (NatureScot email of 20th May 2022), during the non-breeding period guillemots are assumed to remain largely within the waters in the region of the breeding colony, as defined by the mean maximum foraging range plus 1 SD (Woodward et al. 2019, Buckingham et al. 2022, volume 3, appendix 11.5 of the Offshore EIA Report). Therefore, on this basis, the Proposed Development has a similar potential to have effects on the St Abb’s Head to Fast Castle SPA guillemot population during the non-breeding period as during the breeding season, with 33% of the guillemot occurring on the Proposed Development array area during the non-breeding period estimated to derive from this SPA colony (volume 3, appendix 11.5 of the Offshore EIA Report).
Project alone: construction and decommissioning
Disturbance
  1. As described for kittiwake, direct disturbance to guillemots during the construction phase may arise within the Proposed Development array area (and it’s 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.
  2. 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).
  3. When using the marine environment (and not at the breeding colony), guillemots 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 guillemot 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).
  4. 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 guillemots from the St Abb’s Head to Fast Castle SPA. Thus, the Proposed Development array area encompasses 1,010 km2, whilst the Proposed Development export cable corridor encompasses 168 km2. Together these areas represent approximately 3% of the total breeding season foraging area that is potentially available to the SPA guillemot population, as defined by the generic measure of the species’ mean maximum breeding season foraging range plus 1 SD (i.e. 73.2±80.5 km - Woodward et al. 2019) and assuming that this range is represented by a semicircle to the seaward side of the colony. Similarly, the Proposed Development Array and export cable corridor represent approximately 14% of the breeding season foraging area if considering the mean maximum foraging range only. Additionally, modelling of guillemot 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 overlap with waters that are predicted to be used by birds from the St Abb’s Head to Fast Castle SPA and (except for a small part of the Proposed Development export cable corridor) exclude those areas of predicted greatest usage (Cleasby et al. 2018).
  5. During the non-breeding period, guillemot distribution is less constrained by the location of the breeding colonies but (as detailed above), for the purposes of the current assessment, it is assumed that the area occupied by the SPA population is defined by the mean maximum breeding season foraging range plus 1SD. Thus, the potential for effects of construction-related disturbance is assumed to be similar to that during the breeding season.
  6. 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.
  7. 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.
  8. Given the moderate sensitivity of guillemot to disturbance effects, 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 St Abb’s to Fast Castle SPA guillemot population.