Offshore wind energy - sectoral marine plan: seabird tagging feasibility

Executive summary

Following the completion of the ScotWind Leasing round, seabed Option Agreements were put in place for 20 new offshore wind farm projects in Scottish waters, with a capacity in excess of 27 GW. However, the Habitats Regulations Appraisal carried out in relation to the Sectoral Marine Plan (SMP) for Offshore Wind^[1] highlighted the potential for significant, negative cumulative impacts on some populations of seabirds. Consequently, several of these lease areas, off Scotland’s east coast, are considered to be under the highest levels of ornithological constraint, meaning developments cannot proceed unless evidence can be produced to demonstrate that impacts are at, or can be reduced to, an acceptable level. The SMP Roadmap of Actions highlighted the potential value of seabird tracking studies for producing this evidence. This report aims to build on the SMP Roadmap of actions by:

• Producing a summary timeline detailing the key tasks for a seabird tracking project from inception to delivery;
• Producing recommended protocols for tagging, covering tag types, capture and attachment methodologies;
• Identifying sites where additional tagging work is both feasible and necessary through consultation with local researchers, ringers and fieldworkers and site visits.

Whilst there has been extensive seabird tracking work at Scottish breeding colonies, most of this has taken place at sites where birds are less likely to be exposed to the impacts associated with the ScotWind projects. Consequently, given both the potential scale of tracking projects required, and the need to work at new sites, the Roadmap of Actions highlighted the need for a study to assess the feasibility of the proposed work. The key species of interest are gannet (Morus bassanus), kittiwake (Rissa tridactyla), herring gull (Larus argentatus), great black-backed gull (Larus marinus), guillemot (Uria aalge) and razorbill (Alca torda) breeding within the following Scottish Special Protection Areas (SPAs): St Abbs Head to Fast Castle, Forth Islands, Fowlsheugh, Buchan Ness to Collieston Coast, Troup, Pennan and Lions Heads, East Caithness Cliffs, North Caithness Cliffs, Copinsay and Fair Isle.

This report highlights the steps that must be taken when planning a successful tagging study, starting in the December prior to any fieldwork when tags must be ordered and permission to work at a site and deploy tags must be sought, through to the breeding season in the post deployment year when return rates should be assessed and any devices deployed over winter should be retrieved. We summarise the types of devices available and the strengths and weaknesses associated with these devices and highlight the methodologies that can be used to capture the species concerned and attach the selected devices. Finally, based on a review of existing and ongoing tagging studies, and visits to some of the key sites during autumn 2022, we make recommendations for work during the 2024 or any subsequent breeding season.

At present, tracking studies are planned by a range of organisations for gannets (Forth Islands SPA), kittiwakes (St Abbs Head to Fast Castle SPA, the Forth Islands SPA, Fowlsheugh SPA and Buchan Ness to Collieston Coast SPA), guillemots (Forth Islands SPA and Buchan Ness to Collieston Coast SPA) and razorbills (Forth Islands SPA and Buchan Ness to Collieston Coast SPA). It is recommended that tracking studies on great black-backed gull are not undertaken at present as devices fitted with standard attachment methods are quickly removed by the birds and there are concerns about device effects associated with harnesses. Until such a time as the device effects associated with harnesses can be reduced to an acceptable level, deploying GPS tags on great black-backed gulls is unlikely to be considered a viable approach. Puffin was not considered for inclusion in this feasibility study, and tag effects are a known concern for this species. Following site visits in autumn 2022 and discussion with site staff, it is also advised that tagging gannets on Fair Isle SPA, or at Troup, Pennan and Lions Heads SPA is not feasible due to health and safety concerns. Given the locations of the Forth Islands SPA and St Abbs Head to Fast Castle SPA relative to the ScotWind sites and, the ongoing bird tagging work within these SPAs, it is felt that additional data collection at these sites to support ScotWind is less of a priority at present. However, it is recommended that additional visits to sites within Fowlsheugh SPA, Buchan Ness to Collieston Coast SPA, Troup, Pennan and Lions Heads SPA, East Caithness Cliffs SPA, North Caithness Cliffs SPA and Copinsay SPA are undertaken during the 2023 breeding season to further assess the feasibility of deploying tags at these sites in future years. Many of these visits are planned as part of ongoing work during 2023.