3. TIER I: SAFEGUARDING KITTIWAKES AT DUNBAR

3.1. Background

266. Dunbar Castle, harbour and the adjacent coast supports a considerable number of breeding seabirds, with >800 pairs of Kittiwake and smaller numbers of Northern Fulmar (16 pairs in 2020), European Shag (16 pairs in 2020) and Herring Gull (15 pairs in 2020). The compensation at Dunbar would therefore be of benefit to Kittiwake only and not the other key species.
267. Although numbers are low compared to the larger colonies, such as St Abbs and the Isle of May, Dunbar supports more Kittiwakes than Coquet and more than any of the Forth Islands, with the exception of the Isle of May (Figure 3.1) making it a significant local colony.
268. Funding a warden for the Kittiwake colony at Dunbar Castle (a non-designated site) was recommended during stakeholder consultation to improve the numbers of adults nesting at Dunbar and their breeding success. Improving breeding success at Dunbar would strengthen Kittiwake populations within the Forth Islands and Farne Islands SPAs. Ringing of Kittiwakes at Dunbar between 1993 and 2007 resulted in the capture of 16 ringed birds from other sites, proving connectivity with the Isle of May (10 birds), Inchkeith (4 birds) and the Farne Islands (2 birds) (Coleman et al. 2011)[22].
269. Problems with the site identified during stakeholder consultation included human disturbance, and discarded fishing nets left around the harbour, which then become incorporated in Kittiwake nests leading to risks of entanglement/ingestion (see Section 3.3 below). It was felt that a warden would be able to liaise with both the public and the fishermen to resolve these issues. Further consultation with East Lothian Council (ELC) and the Dunbar Harbour Trust (DHT) confirmed this assessment of the situation, and the benefits of having a ‘Kittiwake warden’ were unanimously agreed.
270. Following the Applicant’s Compensation Consultation meeting 30 March 2022, concerns were raised by NatureScot regarding the uncertainty and time that it would take to research and implement the measures suggested for Kittiwake at Dunbar. It was suggested that poor prey availability could be the driver for the decline at Dunbar and that wardening may not be an effective method to increase productivity. The need for habitat enhancement was questioned on the basis that there is spare nest capacity with possibly 300-500 spaces already available. The unquantified nature of the disturbance impacts, and the anecdotal nature of the evidence was also raised as being of concern[23].
271. Further work regarding the disturbance issues at Dunbar and evidence regarding the prey situation from Searle et al. 2022 (in prep.) were presented at the Compensation Consultation meeting on 8th June 2022 and are discussed in full within this report. Following this additional work there was a consensus from NatureScot, Marine Scotland Science and RSPB that human disturbance is an issue at Dunbar, and that reducing disturbance ‘would likely improve productivity of the Dunbar Kittiwake colony’[24].
272. The focus of comments related to: i) how the benefits of wardening would be assessed and quantified, ii) to what extent the wardening would provide ‘significant measurable benefits’, and iii) the need for evidence relating to the various types of human disturbance and which may be the most damaging for the Kittiwakes. The anecdotal nature of the evidence was again raised, as was the requirement to account for the adverse impact of the Proposed Development on the Dunbar Kittiwake colony as a component of this assessment[25].
273. A brief summary of how the benefits of wardening could be measured, quantified and assessed, is included in Section 3.3 and further details are included in the Implementation and Monitoring Plan. Further study of the various types of human disturbance and their impacts on the Kittiwakes would need to be carried out.
274. It is not possible to define to what extent this project will improve colony productivity in advance of the work being undertaken. However, Section 3.3 sets out a series of hypotheses and how these could be tested. As a starting premise, the data presented in Searle et al. 2022 (in prep.) suggests that prey is not a limiting factor, therefore implying that colony-based issues are driving the decline in the Dunbar Kittiwake colony. In essence this project allocates resource to systematically and scientifically investigate and tackle the various factors that may be impacting negatively on the birds to improve productivity. For this reason, monitoring and adaptive management is recommended so that it can be agreed that the resources are being directed appropriately and that the project is delivering measurable benefits. It is anticipated that the data from the project could be reviewed annually. This approach has the benefit of allowing the project to evolve in accordance with the needs of the site, which are likely to change over time.
275. As the site is neither a SSSI nor an SPA it does not currently have a dedicated warden, although the birds are counted annually by the East Lothian Countryside Ranger Service (ELCRS), who have also monitored colony productivity in the past. Kittiwakes from Dunbar are also ringed by a local group. Since there is no resource to gather any other data from Dunbar, the information presented within this report is to a certain extent anecdotal, although many observations are from the local ELC Warden with >20 years of experience working within this Dunbar Castle area and are considered (in the absence of any other formally gathered data) to represent the best available information.

3.2. Site description

3.2.1.    History of the Dunbar Kittiwake Colony

276. The Kittiwake colony has a well-documented history due to its accessibility. In 1934, 3 nests were recorded. The colony increased between 1934 until the late 1950s reaching 201 nests in 1959 (Coulson 1963, 1983). It then underwent a period of decline from 1959–1976, with 189 nests in 1976 (Coleman et al. 2011). From 1976–2000 the colony continued to increase. Prior to the 1980s, the Kittiwakes nested in the Granary, although they abandoned that nesting site when it was renovated. It is unlikely that they will nest there again, as it is now occupied.
277. During the 1980s the Kittiwakes expanded to occupy nesting areas around the North and South Harbour entrances and the Magazine (a former weapons store). In 1995 a large quantity of masonry from the Castle fell into the sea, and the Castle was closed to visitors on health and safety grounds.
278. It seems likely that at this point a reasonable proportion of the Kittiwakes nesting on the main colony relocated to the Inner Castle, which was no longer accessible to people (see Figure 3.4). Use of the cliffs adjacent to the Leisure Pool also started around this period, and the Kittiwakes also started to nest on the various rock outcrops, which were formed by the collapse of the Castle into the sea. The nesting area on the leisure cliffs is of specific interest as the number of birds in this location have been gradually increasing, numbering 152 nests in 2021. This area is not accessible to people (Table 3.1, Figure 3.4).
279. The Kittiwakes now nest in a variety of locations around the main Castle, ruins, harbour and surrounding cliffs (Figure 3.1, Table 3.1). However, they do not nest on any residential buildings as is often the case in urban locations.
280. The number of Kittiwake nests on the main Castle has been steadily declining since the late 1990s, although total numbers of Kittiwake nests at Dunbar continued to increase until the early noughties reaching a peak of 1,191 nests in 2000. However, it is the sustained decline in nests on the main Castle that appears to be the driving the general trend of decline at this site (Figure 3.3 and Figure 3.4). The most recent count from 2020 recorded 808 nests, with only 153 nests on the main Castle (Figure 3.3, Table 3.1). Since the habitat itself is unlikely to have changed appreciably, and the main Castle remains in many ways superior to some of the other areas used, such as the Sea wall which is regularly flooded out and the outcrops which are lower and very exposed, it is speculated that the decline may be due to increased human disturbance and could potentially be rectified.

3.2.2.    Stakeholders & ownership

281. Dunbar Castle was formerly owned by ELC, who still have responsibility for monitoring Kittiwake numbers. Ownership of the castle itself was transferred in 2004 to the Dunbar Harbour Trust (DHT), a charity set up by a number of harbour users with the aim of improving the harbour facilities for the professional and leisure users. The Board’s mission statement is to ‘run a safe, efficient and welcoming harbour that caters for the needs of all the harbour users, visitors and the local community as well as the environment’.
282. One of the strategic objectives identified by the Board is improvement of the environment within the harbour. The Castle itself is a Scheduled Monument, and the whole of Dunbar Harbour is a historic conservation area. Although the Castle has played an important role in Scotland’s history, it is in considerable disrepair and there are no plans to restore or conserve it, although work to prevent further collapse is occasionally undertaken.
283. Dunbar Harbour itself is small with 28 fishing vessels and around 60 members. It is also popular with leisure users, and every leisure mooring is currently taken. The fishing vessels are 6–15 m in length and generally fish locally for Norway Lobster (Langoustine) Nephrops norvegicus and crabs. The Harbour is inaccessible to larger vessels as the entrance is difficult to navigate and has problems with surge.

3.2.3.    Number and location of Kittiwake nests

284. The number and locations of Kittiwake nests are shown in Figure 3.2, with Table 3.1 showing how the distribution of nests has changed over time. Changes in the number of birds nesting in each of sub-sites is plotted in Figures 3.3 and 3.4.
285. The decline in nests on the main Castle described above is mirrored by similar declines on the north Harbour entrance and the south Harbour entrance, with declines in all three areas starting during the mid to late 90s (Figure 3.4). In the mid-90s, there were ~250 nests on the south Harbour entrance and >100 nests on the north Harbour entrance. By 2020 this had declined to 132 nests on the south Harbour entrance and 20 on the north Harbour entrance.
286. The main Castle, the north Harbour entrance and the south Harbour entrance can all be accessed via a footpath. The path that runs along the main Castle colony and the green in front of the steps are the key areas where there is greatest overlap between the public and the Kittiwakes. At present people, dogs and children (in unlimited numbers) are able to walk along the narrow path that directly abuts the outer wall of the main Castle where the Kittiwakes nest (see cover photo). There is no signage and the majority of people using the path will be unaware of the birds nesting metres away. The green right next to the Castle also allows the public to walk virtually right up to the colony. 
287. The north Harbour entrance can be accessed via footpath in a similar manner to the main Castle, although it is not possible to walk all the way along. The south Harbour entrance is not accessible. Increased marine recreational use of the harbour may also be responsible for the declines in these areas as the harbour entrance is only ~20 m wide.
288. The number of nests on the (inaccessible) Leisure Pool cliffs has been gradually increasing. Although numbers of birds nesting in the Inner Castle have also been increasing, over recent years numbers have dropped reducing from ~296 in 2015 to 218 in 2020, although further years data will be required to confirm that it is a genuine decline rather than natural variation.
289. Although the magazine is also inaccessible to the public and is located close to the Leisure Pool cliffs, the number of nests in this location has declined over the past decade from around 150 nests in 2010 to only 62 in 2020. The reasons for this decline are unclear. The small number of birds nesting on the rocky outcrops and sea wall has remained relatively constant over the past twenty years, suggesting that these areas may be at capacity.
290. In general, there has been a re-distribution of birds away from the more disturbed areas, namely the main Castle and the north and south harbour entrances in favour of less accessible sites such as the Inner Castle (fenced off to the public), the leisure pool cliffs and the rocky outcrops (inaccessible). However, despite this re-distribution, there is still an underlying trend of decline in overall numbers of nests at Dunbar driven by the decline of nests on the main Castle.

3.2.4.    Colony productivity

291. Productivity data is available for the site from 1990–2015 (Table 3.2, Figure 3.5). Recording stopped in 2015 due to lack of resource. However, the location of the monitoring plot will need to be moved from the main Castle as there are now too few nests in this location (T. Sykes, ELCRS, pers. comm.).
292. Average annual productivity over the 25 years is 0.83, which mirrors JNCC productivity data for Scotland from 2009–2019[26]. However, productivity was very low between 2004 and 2008, coincident with the mass appearance of Snake Pipefish Entelurus aequoreus and poor breeding success at a number of colonies nationwide. In these years, chicks starved and mortality rates were 50–60%. In many cases chicks were found emaciated and choking on Snake pipefish, which they were unable to swallow due to their long and cartilaginous structure. In 2013 the colony suffered a very severe storm, which resulted in the loss of many chicks and adults due to exposure (T. Sykes, ELCRS, pers. comm.).
293. When fledglings and adults are ringed, data is gathered on their body mass. Between 1993-2007 there was a reduction over time in nestling body mass combined with larger numbers of nestlings dying even though colony size increased. It is speculated that poor prey availability was responsible for declines, although no decline in adult body mass was recorded (Coleman et al. 2011).
294. Although Kittiwakes may lay up to 3 eggs, clutch size decreased to just a single egg during the period from 2004-2008. Although the situation has improved, and many birds now lay 2 eggs and go on to successfully fledge two chicks, there are no nests with 3 eggs, again indicating that prey supply is potentially poor (T. Sykes pers. comm.). However, this is not unique to Dunbar, and reflects the situation throughout the local Forth area.

Figure 3.1: Numbers of breeding Black-legged Kittiwake expressed as Apparently Occupied Nests (AON) from 1986 to 2019 (or 2020) at selected SPAs or reserves on the east coasts of Scotland and England.

Figure 3.2: Location of Kittiwake nesting areas within Dunbar Harbour and surrounding coastline. 

Figure 3.3: Number of Kittiwake nests (AON) at Dunbar by location.

Figure 3.4: Trends in abundance of Kittiwake nests in the various sub-sites that comprise the Dunbar colony

Table 3.1: Number and location of Kittiwake nests from Dunbar Castle and surrounding coastline from 1979-2020. Numbers relate to areas shown on Figure 4.2 Data supplied by East Lothian Council[27]

Table 3.2: Productivity monitoring from Dunbar Castle 1990–2015. Data from East Lothian Council.

Figure 3.5: Changes in productivity (number of chicks fledged per pair) from Dunbar 1990–2015.

3.3. Project Description

3.3.1.    Stakeholder meeting

295. An online meeting was held on 27th December 2021 with the relevant stakeholders (DHT, ELC and ELCRS) to discuss the objectives of the warden, how the warden might interface with the workings of the harbour, working facilities and logistics. The description of the project is derived from this process, and therefore has the in-principle support of all stakeholders. This report outlines very briefly how the wardening would work on a practical level but is primarily focussed on presenting the evidence behind why wardening has been recommended at Dunbar. Further detail on the delivery of the project is located within the Implementation and Monitoring Plan
296. It was agreed that the objectives of the warden would be to identify limiting factors and implement solutions to improve both the number of birds nesting at Dunbar and their breeding success. The warden would also work closely with the Dunbar Harbour Trust and engage with both the fishermen and other users of the harbour as well as the general public.
297. Given that duties would be beyond what might normally be associated with a wardening post, it was agreed that the term warden/researcher might be more suitable. Although there is information available about the colony, it is not comprehensive and further study will be required to either identify or confirm the actions required. Furthermore, the issues may change over the lifetime of the project so the warden/researcher would need to be able to identify emerging issues, and where necessary gather data and develop solutions.
298. The factors believed to be limiting colony success at present are discussed in further detail below. Tackling these factors would, at least initially, constitute the main elements of the warden/researcher’s job.

3.3.2.    Human disturbance

299. The issue of human disturbance is highly relevant to Dunbar because of the number of people using the Harbour, the range of potentially disturbing activities undertaken, and the decline in the number of Kittiwake nests in areas that are accessible to the general public. Although the impacts of human disturbance have often been dismissed as minor in nature, and therefore inconsequential in relation to the more commonly acknowledged pressures such as prey availability and extreme weather events, there is increasing evidence that suggests human disturbance can cause a measurable and significant level of harm in certain circumstances.
300. Although direct mortality of birds due to human disturbance has been recorded in a few circumstances (Yasue & Dearden 2006, Lilley 1999), this is rare. However, there is now a significant body of work that demonstrates reduced breeding success in locations where disturbance is greater (Arroyo & Razin 2006, Ruhlen et al. 2003, Bolduc & Guillemette 2003, Murrison 2002). There are also an increasing number of studies showing how birds view habitats as lower quality if they are regularly used by people (Mallord et al. 2007, Gill et al. 1996, Bötsch et al. 2018, Remacha et al. 2016) and there are many examples of otherwise suitable habitat being unused because of disturbance (Gill 1996, Kaiser et al. 2006, Liley & Sutherland 2007). A few studies have now been able to demonstrate that human disturbance may result in population level impacts (Liley & Sutherland 2007, Mallord et al. 2007, Stillman et al. 2007, West et al. 2002).

Figure 3.6: The area in front of the main Castle is becoming increasingly disturbed. Fishermen are using this area to store creels, and it is thought that this attracts rats which alongside increased human disturbance, is thought to be responsible for the decline in the number of nests in this location.

301. The negative impacts of human disturbance on ground-nesting shorebirds were identified some time ago (Carney & Sydeman 1999) and the benefits of fencing areas to improve the breeding success of ground-nesting shorebirds and terns are widely acknowledged (Verhoeven et al. 2022, Babcock & Booth 2020b). Non-electric fences protect areas from disturbance by humans and dogs (Babcock & Booth 2020b), whilst electric fences also exclude mammalian predators such as foxes (Verhoeven et al. 2022). Wardens are necessary to ensure that people and dogs remain outside of fenced areas, particularly in busy locations, and positive engagement with the public is required to achieve this. People are considered more likely to behave in a reasonable way if they are being observed (Babcock & Booth 2020b). However, the value of fences and wardening for cliff-nesting species are less clear. These species are already nesting in inaccessible areas and there is a perception that little can be done to help them.
302. However, there is increasing evidence that human disturbance also impacts on cliff-nesting seabirds. Heart-rate monitors attached to Kittiwakes nesting near the path at St Abbs National Nature Reserve (NNR) showed that birds experienced a rise in heart rate as a consequence of stress when visitors were close, even though no external behavioural response was observable (Beale & Monaghan 2004).
303. The results of another disturbance study on Gannet at Great Saltee, an unmanaged island reserve offshore of Ireland, were also surprising. Gannet is generally assumed to be a robust and approachable species and is thought to be tolerant of both humans (presumably because numbers have been increasing at virtually all colonies). Allbrook and Quinn (2020) found that the percentage of successful nests declined with proximity to the edge of the colony. Nestling success averaged 0.33 chicks fledged per nest in the disturbed area compared to 0.52 in the undisturbed control. The study also concluded that visitor proximity to the colony reduced in the presence of an information sign. One of the authors on a single day observed 10 separate incidents of egg predation from gulls caused directly by human behaviour. This demonstrates that human disturbance can also impact indirectly on nest success (Allbrook & Quinn 2020).
304. Another recent study has been able to quantify the impacts of human disturbance on colony productivity. A study on European Storm Petrels nesting on Mousa, a small uninhabited island in Shetland, showed that nestling mortality was higher in areas exposed to high visitor pressure and that overall colony productivity was reduced by ≤ 1.6% compared with that expected in the absence of visitors (Watson et al. 2014). The results of this study were surprising because it had always been assumed that Storm Petrels were not impacted by human disturbance. Like many other burrow- and cavity-nesting seabirds, Storm Petrels are only active within the colony at night. During the day, birds either remain in the underground nest, out of sight, or are foraging at sea. Storm petrels prefer dark chambers and nests are usually at least 30 cm below ground and without a direct view to the exterior; therefore, there is no visual contact between human visitors and the storm petrels (Watson et al. 2014).
305. These studies demonstrate that human disturbance can impact on seabird productivity, even in remote locations where there is no obvious disturbance problem. By contrast the Dunbar Kittiwakes are subject to various differing and constant disturbance sources.
306. Wardens are typically employed to prevent damage to wildlife and to provide information to visitors. They may also carry out other activities such as monitoring, reporting, habitat improvement, repair, dealing with emergencies (fire, flooding, storm damage), litter removal, guided talks, and training and supervising volunteers. They may also be responsible for enforcing wildlife law by passing on details of wildlife crime to the police. The concept of having a warden to look after a seabird colony is not a new one. In 1861 Archdeacon Charles Thorp arranged the purchase of some of the Farne Islands and employment of a warden to protect threatened seabirds. The idea of having a warden to protect animals is derived from the medieval gamekeepers who stopped any intruders from hunting the King’s deer. The concept of having a warden present on site to prevent others instigating damaging behaviour remains unchanged.
307. The value of wardening reserves supporting nationally and internationally important numbers of birds is generally acknowledged and relates directly to the conservation value of the species concerned. A need for wardening may also arise in response to conflicts between wildlife and people occupying overlapping spaces. For example, in east Norfolk a local volunteer scheme, the Friends of Horsey Seals, was initiated to reduce disturbance of breeding Grey seals by people and dogs. This voluntary wardening scheme has been extremely successful; seals and people are physically separated by fences and visitors are restricted from the beach and channelled along a path. This has reduced disturbance to the seals, whilst the presence of wardens has created a safer and more informative experience for visitors. The colony has expanded both geographically and in terms of numbers of pups born. Although this increase reflects national trends, the scale of colony expansion at Horsey is still notable.
308. The benefits of a warden are clear, and all the activities typically undertaken by a warden would be of significant benefit at Dunbar; the Kittiwake colony has a problem with fishing litter, engagement with the local community is required to foster a better sense of ownership of the colony in general, the site would benefit from habitat enhancement, and a warden and volunteers would be able to gather information on the birds, which is currently lacking. The presence of a warden would prevent some of the behaviour that at times results in police involvement. With a warden visitors can be kept away from the immediate vicinity of the colony, but in return receive a more informative experience by talking to a warden, learning about the Kittiwakes and even seeing nests and chicks through a telescope. The Kittiwake colony is so close to the town and working harbour, which is also a busy tourist spot, that a permanent warden is considered a necessity in safeguarding the colony and ensuring the site’s success in future years. 
309. The East Lothian Visitor Survey carried out in 2021 showed that Dunbar is second most visited town in East Lothian (after North Berwick) and was visited by 40% of tourists staying in the area (STR 2022). Dunbar Harbour is a scenic and historic site supporting not only the Castle, but an old fort (The Battery), a converted granary (now the Dunbar Harbour Trust), and a magazine where ammunition was historically stored. Dunbar has previously been the recipient of a £4 million grant from the Heritage Lottery Fund to support the regeneration of the historic urban environment (https://www.shbt.org.uk/our-projects/dunbar-townscape-heritage-initiative/).
310. The DHT was incorporated in 1999 with the objective of ‘operating the harbour for the benefit of port users and the local community…as well as becoming a focal point for the local community’. The DHT has implemented various projects to improve the area and improve access to the Harbour and to enhance appreciation of its historical features. The largest of these projects was renovation of The Battery in 2017. This project has transformed this ruined fort (located ~200 m from the Kittiwake colony) into an outdoor events venue that now hosts regular music and theatre events as well as community festivals. There is now a Dunbar Battery Theatre Company, and an aspiration to increase its use and make Dunbar Harbour a ‘go-to’ place in East Lothian for the performing arts. The impacts of these events on the Kittiwakes have not been monitored, although it is speculated that the renovation of The Battery may be associated with the suspected decline in nesting Kittiwakes in the Inner Castle in recent years.
311. Offshore recreational use of the Harbour and surrounding waters for water sports is also increasing and activities undertaken locally include kayaking, paddle boarding, diving, sailing, coastal rowing and surfing. The impacts of these various activities on the Kittiwakes are also unstudied.
312. Use of the harbour is thought to have increased significantly as an area for walking both by locals and visitors, especially over the last two years It is understood that visitor numbers have trebled due to the popularity of ‘staycations’ during the SARS-Cov-2 pandemic when overseas travel has been restricted (T. Sykes East Lothian Countryside Ranger Service pers. comm.). This reflects general trends observed in both East Lothian and the UK during the pandemic for increased uptake of outdoor activities such as hiking, outdoor swimming and trips to the beach in preference to indoor attractions (STR 2022).
313. On occasion, local children throw stones at the Kittiwakes nesting on the main Castle. This may be especially damaging if the disturbance takes place early in the season before eggs are laid. If the ELCRS is aware and the children responsible are known locally, the police are informed and will talk to parents. If children are not known, it can take longer to resolve. The simple presence of a dedicated site warden is likely to stop such behaviour and would also stop local youth from ‘tombstoning’ (jumping from height into the sea) from near the Kittiwake colony, another activity that is contributing to disturbance in the area.
314. The importance of educating the local children in school is critical in stopping anti-wildlife behaviour and would go a long way in engendering a sense of connection to and ownership of the Kittiwake colony. A warden would be able to undertake visits to local schools to teach children about the lifecycle of the Kittiwake, perhaps coupled with a follow-up trip to the colony to show children nesting birds and chicks using a telescope.
315. During the main tourist season a warden could be on site, perhaps at the Battery, at specific times with a telescope to provide opportunities for both visitors and members of the local community to see the birds in a way that is not normally possible and to learn more about them.
316. Increased vessel movements and people in the harbour can reduce Kittiwake foraging activity. It is known that the Kittiwakes favour feeding and loafing at Belhaven Bay at low water and may be displaced by people and surfers if the beach is busy. In the past, council led social media campaigns have been successful in making the public aware of these types of issues, and it is suggested that this could be taken up again and continued by the warden. Codes of conduct could be developed with local groups to reduce the potential impacts of these activities.
317. Changes in the distribution of nests and the decline in nests on the main Castle and harbour entrances strongly suggests that human disturbance may be causing direct displacement of birds away from key nesting areas, and without intervention it is likely that the current trend of decline will continue. Once colony size decreases beyond a certain level then the birds are more vulnerable to predators, and colony success decreases.
318. The path that runs along the main Castle colony and the green in front of the steps are the key areas where there is greatest overlap between the public and the Kittiwakes. At present people, dogs and children can walk along the narrow path that directly abuts the outer wall of the main Castle where the Kittiwakes nest (see figure 4.6). There is no signage and people walking along this path may very easily and completely inadvertently disturb the birds unaware of their nests just meters away. The green right next to the Castle also allows the public to walk right up to the colony.
319. How birds respond to disturbance is context and species specific and birds may habituate to certain activities over time. However, judging habituation is problematic; for example, in the St Abbs Kittiwake study described above (Beale & Monaghan 2004) the birds did not exhibit any outward response to human disturbance, and it could easily be assumed that they had successfully habituated to the presence of humans on the path. How disturbance could be monitored and assessed at Dunbar is discussed further in section 4.3.7.
320. Further evaluation is needed to determine how the various types of disturbance may be impacting on the birds, and to establish how these may be tackled. Disturbance could be reduced by restricting access to the front face and entrance stepway on the south side of the harbour. Fencing off the green in front of the steps to add a buffer between the Kittiwakes and the public would also be of significant benefit (T. Sykes, pers. comm).
321. Although some of this information is anecdotal by nature, there is reasonable evidence that disturbance is a significant factor at this colony. Lack of targeted data is inevitable as there is currently no funding mechanism to enable information to be collected officially. However, the staff who have supplied information to support this project are experienced professionals and the prospect of having a Kittiwake warden is well-supported locally amongst the relevant stakeholders.

3.3.3.    Prey

322. Although the studies cited above show that human disturbance can potentially impact on colony productivity, it is important to evaluate the role of other known influential factors. JNCC Seabird Monitoring Programme data indicates that Kittiwake numbers increased by around 24% between the late 1960s and the mid-1980s possibly due to the cessation of egg collecting and hunting (Cramp et al. 1974). However, catastrophic declines followed from at least 1986 onwards, and there are now around 50% fewer birds than in the late 1960s (JNCC 2021). Changes in the marine environment due to warmer sea temperatures and the associated decline in the abundance of sandeels is thought to be responsible (Frederiksen et al. 2004). On this basis, poor prey availability due to climate change is routinely identified as being the main pressure affecting this species.
323. Unlike the other Scottish colonies, the number of Kittiwakes nesting at Dunbar increased during the 1990s (Figure 3.1). Productivity data is available for the site from 1990-2015 and over the 25-year period averages 0.83, mirroring the JNCC productivity data for Scotland from 2009-2019. Although productivity is not a direct proxy for prey abundance, there is no apparent evidence to suggest that foraging conditions differed significantly at Dunbar to any of the other local colonies. As mentioned previously it is likely that the increases observed at Dunbar during the 1990s relate to the closure of the Castle to the public resulting in increasing numbers of Kittiwakes occupying the main and Inner Castle areas.
324. Recent analysis assessing the benefits of the existing sandeel fishery closure (implemented in 2000) on local Kittiwake colonies shows that even though the Isle of May and Dunbar are only 40 km apart, breeding success for the Isle of May has increased by 17% since the sandeel fishery closure within the Firth of Forth as offshore foraging conditions have improved, whilst the trend of moderate decline has continued at Dunbar. It is hypothesized that human disturbance is the cause for the differing trends observed at these two colonies (Searle et al. 2022 in prep.). If prey was the limiting factor, then similar increases would be expected at Dunbar to those observed on the Isle of May. The decline at Dunbar suggests there are other local factors affecting the success of this colony, the most obvious of which is human disturbance (see Section 3.3.2).
325. As a general principle, the potential impacts of poor prey availability on colony success must be acknowledged. High Sea Surface Temperature (SST) and poor prey availability, as experienced during 2007 and 2008, resulted in extremely low productivity levels across many Kittiwake colonies. The re-occurrence of similar conditions could negatively impact on the delivery of conservation targets at Dunbar. However, the effectiveness of colony-based measures at any site could be affected by these unpredictable large scale climatic events. 

3.3.4.    Predation

326. Since the prey situation has gradually ameliorated within the Firth of Forth over the last decade, the main cause of chick mortality for Kittiwakes appears to no longer be starvation, but predation by Herring Gull with mortality estimated at ~5% (T. Sykes, ELCRS, pers.comm.). Assuming a colony size of 808 nests, an average of 0.83 chicks fledged per nest, tackling Herring Gull predation would save ~34 chicks per year. However, the indications from stakeholder engagement are that any work that may impacts negatively on Herring Gull in any way will not be viewed favourably.  
327. Rats are also thought to have become a problem in the main Castle. This is believed to be because fishermen have been stacking up old creels next to the castle wall (Figure 3.6). The creels attract rats, which are then able to climb up the creels and predate Kittiwake nests in this area, which is also where the productivity monitoring is carried out. As a consequence, Kittiwake numbers in this area are declining, signifying that the value of the habitat has decreased. The favoured nesting area is now the Inner Castle. The lack of storage space for the fishermen at Dunbar Harbour is an ongoing issue and removing the creels and implementing a rodent control programme over the winter months would be effective in reducing rat numbers and improving the value of the habitat for Kittiwakes.

3.3.5.    Habitat enhancement

328. It was suggested during the stakeholder consultation meeting with DHT,ELC and ELCRS that the site could benefit from habitat enhancement. The need for habitat enhancement was questioned by NatureScot on the basis that there is spare nest capacity with possibly 300-500 available[28].
329. This availability of physical nest space is undisputed, and the estimate of available space seems sensible on the basis that the colony has declined by 400 nests over the past 20 years. In view of the disturbance issues, it is intuitive to focus on reducing disturbance around the main Castle area and harbour entrance, and in so doing encourage the birds to return to these nesting areas.
330. The ruined castle naturally provides ledges, overhangs and shelter, and parts of it (the main Castle and Inner Castle particularly) are considered optimum habitat. The Kittiwakes nest in the cavities left by lost masonry, which has resulted in a network of sheltered nesting areas, many of which benefit from overhangs and which offer more shelter than many natural cliff faces (Figure 3.7).
331. However, nest numbers are declining on the main Castle front and birds are instead nesting in some locations that are considered sub-optimal, particularly the sea wall where nests are always flooded out.
332. However, it is possible that recovery may take time and given that the site suffers from significant levels of disturbance from multiple sources, it may not be possible to tackle all disturbance sources effectively. It is possible that adding extra nesting ledges to areas which are not disturbed but which may already be at full capacity, such as the rocky outcrops, could be an effective way of helping Kittiwake numbers to recover.
333. It has also been suggested that changes in prevailing wind direction in favour of more north-easterly winds may affect choice of nest site, and if this is the case then other nesting areas may now be more favourable. Although further study would be needed to confirm whether this is the case, habitat enhancement could provide scope for adding nesting ledges in areas that are currently preferred.
334. A better understanding of productivity across the different sub-colonies is needed to understand how successful each of the sub-sites are before habitat enhancement can be considered. To date productivity has only been monitored on the main Castle. It is understood that the small numbers of birds nesting on the outer sea wall routinely fail as the nests are too low and they are washed out in storms and/or high tides (T. Sykes pers. comm). Productivity data from other locations such as the rocky outcrops, the magazine and the cliffs are needed to assess whether similar problems are occurring and whether habitat enhancement in the form of more ledges higher up would be of benefit in these specific areas.
335. In general, it is felt that there is scope to carry out habitat enhancement in the future at Dunbar in a manner that will benefit the birds through the provision of additional nesting habitat in more favourable locations. However, a better understanding of the site is required to reduce uncertainty and to ensure that any work planned has the best chance of success.
336. The Magazine has the potential to support more nesting birds if the colony increases. It is also considered to be the area that would most benefit from habitat enhancement. Other areas that would also benefit include Rock outcrop 1 (9), Johnston’s Hole 1 (7), Rock outcrop 2 (11), North Harbour Entrance (4), Johnston’s Hole 3 (12), and Johnston’s Hole 2 (8)[29]. These areas, shown on Figure 4.8, do not contain the same types of tall walls, ledges and overhangs offered by the main castle.
337. Habitat enhancement would involve adding ledges and overhangs in these areas. The overhangs need to be sized correctly to prevent Herring Gulls from landing and predating nests. Nests that occur naturally with overhangs are routinely observed to be successful on the Isle of May for this reason (F. Daunt, pers. comm).
338. In view of the historic value of the site, further liaison will be undertaken involving the local Conservation Officer to agree an acceptable plan for the work. These areas are also challenging to access, so skilled contractors will be employed by the Applicant.

Figure 3.7: In some parts of the ruined Castle the cavities left by lost masonry have resulted in a network of sheltered nesting ledges, many of which also benefit from overhangs, that have been readily exploited by Kittiwakes. Photograph Stephen McKay.

Figure 3.8: Areas that require habitat enhancement. These areas do not contain the same number of ledges and overhangs as the main Castle (see Figure 4.7 above).

3.3.6.    Fishing litter

339. Dunbar appears to be one of the worst Kittiwake colonies for plastic debris (Figure 3.9). A study looking at the presence of plastics in seabird nests examined 3,681 Kittiwake nests from 33 colonies. Only 4% of nests contained plastics, with most colonies containing no debris. The two exceptional colonies in the study were Dunbar and an oil rig in the North Sea, with 31% and 49% of all the nests respectively, containing anthropogenic debris (O’Hanlon et al. 2021). This reinforces comments made during stakeholder consultation that nearly all of the nests at Dunbar have plastic incorporated within them, and that fishermen regularly discard offcuts of net directly into the Harbour.
340. Although it is understood that the DHT and the Harbourmaster have been working to stop this practice and have also introduced the Fishing for Litter initiative[30], it would be helpful to continue and build on this work to ensure that higher standards are attained and maintained.
341. Since Kittiwakes re-use nests year on year, and the plastic is integrated within the nest (Figure 3.9), totally removing all plastic would result in the nests falling apart. Therefore, it is suggested that the danger of entanglement could be minimized by clipping any trailing net or rope. Any available small pieces of plastic that could be ingested would also be removed. It is known that a small number of birds (often adults) perish every year due to entanglement, and this could be avoided by removing the anthropogenic debris. It is harder to know how many birds ingest plastic, but those that do are likely to suffer negative impacts in the longer term (see Section 7.4). The warden would be able to remove debris from most of the nests, although a climbing crew would be required for some of the difficult areas. A warden would also be helpful in ensuring that the colony remains debris-free into the future.
342. It was agreed during stakeholder meetings that a representative of the fishing community should be involved in further discussions regarding the Kittiwake warden so that they are kept aware of what is happening within the Harbour, have a clearer understanding of what the issues are and also what will be expected from them and why.

3.3.7.    Wardening role

343. This section broadly describes the principal components of the wardening role. Full details of how the work would be implemented are presented within the Implementation and Monitoring Plan.
344. Since human disturbance is a key pressure, gathering more information on the different types of human disturbance and how the birds respond is considered a priority. Table 3.3 shows the type of approach that could be undertaken to tackle key questions.
345. Community engagement is central to the success of this work, and an approach that seeks to understand why people are visiting Dunbar Harbour and that takes their needs into account (alongside those of the Kittiwakes) is considered more likely to result in long-term success. This approach would also accommodate the goals of DHT, who would be an important stakeholder in this project.
346. The need to monitor and quantify the success of work undertaken under this project is understood and is in contrast with other wardening work, which is generally undertaken solely for the purposes of conservation. The need to gather scientific data on the warden and how their presence may (or may not) reduce disturbance in order to establish the benefits to the birds is a novel idea, although other studies provide a precedent (Liley & Panter 2017).

Figure 3.9: Photographs of Kittiwakes nesting at Dunbar Castle showing the abundance of discarded net and other anthropogenic debris incorporated into nests.

347. In addition to human disturbance, it is anticipated that the warden would also gather colony counts, map nesting locations and monitor productivity in a number of different locations. Cameras and monitoring equipment could be used to gather data on seabird demographics (attendance rates, chick provisioning rates etc). It is anticipated that the warden would also identify and find mechanisms of tackling other pressures that may be impacting on the birds, such controlling rodent numbers, fishing litter and other items mentioned above. Any major changes or decisions relating to the project will need to be evidence based as it is acknowledged that the needs of the site may change throughout the project lifespan.
348. Since one of the fundamental aims of the project is to foster a better sense of ownership of the colony amongst the local community, undertaking educational visits to schools and public engagement will also form a key element of the work for the warden.  

Table 3.3: Approach to monitoring and assessing compensation benefits of the Kittiwake wardening project at Dunbar Harbour.

3.4. Conservation targets

349. At its peak in 2000 the colony numbered just short of 1,200 pairs. It is speculated that bringing the colony back to this level from the 808 nests observed in 2020 would be a realistic conservation target of ~400 pairs (800 birds). This works out at 23 birds per year assuming a 35-year project lifespan. Although recovery is unlikely to occur in this linear fashion as seabird counts always fluctuate, the conservation benefit is framed in these terms to allow comparison with potential mortality estimates for the Proposed Development.
350. This conservation target seems feasible on the basis that the colony previously supported >1,100 pairs during several years during the noughties (2006, 2007 and 2010). It is thought likely that the birds will recolonise the Castle if it is fenced off to minimise human disturbance, the creels are removed, and the rodents brought under control. If birds are able to nest in the best habitat, then productivity would also be expected to improve.
351. After the Castle and Inner Castle, the Magazine is considered the next best nesting area. If habitat improvements are carried out at the Magazine, then it has the potential to support many more pairs, which would theoretically enable the colony to expand beyond 1,200 AON. Improving the Magazine and the other sub-optimal areas that are currently in use will increase the productivity of any pairs that continue to nest in these locations.
352. Although the nests are generally well consolidated, some trailing net and plastic results in mortality though entanglement. Entanglement is believed to be a cause of death for a few individuals per year (both adults and chicks are susceptible). The risk posed by ingestion of plastic is harder to quantify (see Section 7.4 for further discussion), but a cleaner harbour will reduce the quantity of plastic ingested by foraging birds in the waters around the colony.
353. It was suggested by MSS following the Compensation Consultation meeting on 8th June 2022 that the compensation benefits resulting from the work at Dunbar should be set within the context of predicted mortality impacts from both the Proposed Development and other wind farm sites within the Forth[31]. Although this is a valid consideration, it is not possible as Dunbar is included in a ‘non-SPA’ total count within the assessment for the Proposed Development, and numbers are not presented for it as a colony in any of the other EIAs of local offshore wind farm sites (e.g. Inchcape, Seagreen ,or Neart Na Gaoithe).

3.5. Timescale & mechanism for delivery

354. The mechanism for delivery is presented in full in the Implementation and Monitoring Plan and only an overview is provided here.
355. There is local support for the work with positive engagement from both ELC and DHT, and there are no reasons why implementation of the measure cannot be rapid.
356. It is suggested that the Dunbar Kittiwake warden would employed through the ELCRS (part of East Lothian Council) with the post funded by the Applicant, although they would also work closely with the DHT and other local stakeholders.
357. The items related to the general protection of the site could start from mid-March when the birds return, as could the education initiatives, improving public awareness of the colony through social media, and liaison with the fishermen regarding fishing litter. Much of the data gathering, for example counts, productivity, provisioning rates, and predator monitoring could also be carried out on the birds return in mid-March.
358. Rodent control should be done during the winter and could be implemented over the winter when the birds are not present. Similarly, removal of plastic from nest sites needs to be carried out over the winter, and liaison with the Council and Conservation Officer will be required beforehand due to the building’s historic status. It would also be necessary to employ contractors to access the more difficult nesting areas.

3.6. Additionality & uncertainty

359. Since Dunbar is not designated for nature conservation, none of the recommended improvements would happen without an additional external funding source. Although the council have maintained a responsibility for counting the Kittiwakes, there is no funding to deal with any of the other aspects described, and productivity monitoring was stopped in 2015 due to lack of resources. Therefore the only item that is already being carried out at the time of writing are the annual bird counts.
360. The DHT states that one of their objectives is to improve the environment within the harbour. It could be argued that this does overlap in a minor way with the role of the Kittiwake warden, particularly with regards to liaison over fishing litter. However, the DHT is a charity and its resources are also limited. A dedicated warden would be helpful in reinforcing these messages and would be able to ensure that better standards are attained and maintained in the longer term.
361. Whilst a conservation target of 800 birds seems reasonable, it is uncertain how long it will take to achieve given that the factors limiting the success of the colony are not completely understood. However, it appears that the issues are colony-based rather than prey-based (Searle et al. 2022 in prep) then it is possible that the response could be rapid if disturbance can be tackled successfully.
362. Although the measures are tried, tested and deliverable as they represent standard conservation management practice, the need to monitor their success in order to quantify the benefits of the project is not standard practice, although other studies set a precedent (Liley & Panter 2017). Dunbar Castle is a Scheduled Monument, and Dunbar Harbour is a historic conservation area. With careful design and the use of non-invasive installation techniques, the Applicant does not anticipate the need for a licence. If a licence is required, an application would be made to HES. However, as non-invasive installation techniques would be used to avoid any structural damage to the scheduled monument and these techniques would be agreed with HES, as well as the fact these measures has support from the landowner, the Applicant does not foresee any impediments to gaining such a licence if it was required.
363. There is some uncertainty regarding the scale of human disturbance impacts at the site, and also to what extent disturbance can be minimised. There are no obvious issues with fencing off the green so that there is a buffer area between the public and the breeding Kittiwakes. In addition, DHT have confirmed that the fishermen do not have the right to store creels at the front of the Castle, although this does require their active engagement and willingness to reduce disturbance to the extent that is desired.
364. It is possible that the Kittiwakes may be cautious about returning to the Castle, even if disturbance is reduced, as birds typically return to the same place to breed. However, it is anticipated that young birds nesting for the first time would fill in the area should this occur.
365. Educating children and the wider public may not directly lead to an improvement in the success of the colony. However, it is still considered of essential importance if Kittiwakes and humans are going to co-exist successfully in such close proximity into the future.
366. Similarly, it may be difficult to quantify the benefit of removing trailing net/rope and small potentially ingestible plastic items from the nesting area (and general harbour). However, the removal of these plastics follows the holistic principles set out in the main Derogation case whereby compensation is potentially strengthened by tackling multiple limiting factors whenever possible.
367. In summary, the provision of a site warden and potential management of disturbance and any other factors that may be negatively impacting on the Dunbar Kittiwakes is additional to the work currently undertaken at this site, which is limited to annual colony counts. Since recent research indicates that the issues at Dunbar to relate to colony management rather than prey (Searle et al. 2022, in prep.), then there is reasonable certainty that the project would be effective in improving the success of this locally important colony.