White-tailed Eagle Reintroduction in Pembrokeshire

Preamble

Our consideration of the proposal to introduce White-tailed Eagles, Haliaeetus albicilla, to Pembrokeshire by the Durrell Wildlife Conservation Trust, Eagle Reintroduction to Wales project, (ERW) will be guided by the following:

1. The IUCN guidelines on re-introductions identify 19 conditions that should be met prior to are-introduction scheme of which we think the following to be of particular relevance: 

• The species must be shown to have been previously present in the region.
• After re-establishment the species should be self-maintaining.
• There needs to be a sound knowledge of the species’ natural history.
• There should be an understanding of the likely ecological effects.

2. The Trust position on re-introductions. In addition to recognising the IUCN guidelines we will only undertake or support any species re-introduction:

• When we are confident that we understand the drivers of previous extinction.
• When all the circumstances that led to extinctions have been addressed.
• When there is robust ecological evidence for the likelihood of a successful re-introduction. 

3. The precautionary principle:

• Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation. (The Rio Declaration Principle 15)

4. The globally important populations of seabirds:

There is a wealth of literature, scientific and popular, along with decades of monitoring data concerning the outstanding, globally important seabird populations of Pembrokeshire. 

The main seabird colonies are classified as the Skomer, Skokholm and seas off Pembrokeshire SPA. The following extract is from the JNCC designation: ‘The islands of Skomer and Skokholm support the largest concentration of breeding seabirds in England and Wales. They hold the largest breeding colony of Manx shearwater in the world (considered to be 316,000 pairs), one of the largest colonies of lesser black-backed gull in Britain (currently over 10,000 apparently occupied sites), as well as being important Welsh breeding sites for other seabird populations, such as razorbill, black-legged kittiwake, Atlantic puffin and common guillemot, supporting a breeding seabird assemblage of over 394,000 birds.’   Recent survey results suggest that the total population of seabird in the SPA is currently over 550,000 birds.

WTSWW has an overwhelming obligation to protecting seabirds on our Islands and we extend that obligation to the mainland birds.

5. Scientific evidence and advice:

We have consulted, Professor Stephen Votier, Professor Tim Birkhead, Professor Chris Perrins, Professor Tim Guilford, and Dr Matt Wood. 

A number of academics sit on our Islands Conservation Advisory Committee, sea bird sub-group (ICAC) and between them, have decades of experience in researching the seabirds and other wildlife of Skomer and Skokholm Island.  In addition, the Wardens of Skomer and Skokholm Island and Bird Observatory were consulted. 

6.  Documents and evidence provided by ERW:

• Eagle reintroduction to Wales, frequently asked questions.
• The ecological roles of Eagles.
• An evidence-based assessment of the past distribution of Golden and White-tailed eagles across Wales (Williams S et al 2020).
• A presentation made to WTSWW by Sophie-Lee Williams of ERW on 11 November 2021.

Discussion

The distribution map in (Williams S Et al 2021) was included in the 11 November presentation but contained no conclusive evidence to show that White-tailed eagle previously bred in Pembrokeshire.

The information presented by the ERW project talked of impact on waders but did not mention seabirds, or the likely ecological effects on the SPA, SAC, SSSI features on the Pembrokeshire islands and mainland. 

In addition to the presentation and literature presented by the ERW project, we are also aware of the general background literature on white-tailed eagles. Their diet is particularly relevant, given that it comprises a significant percentage of birds. Gulls, Auks and even Gannets are all described as prey, for example, Hipfneri et al 2012.

There are concerns about the direct implications of predation but we believe that the level of disturbance and the advantages offered to other avian predators is probably much more significant.

A note prepared by Duncan Halley, a strong advocate of Eagle introduction, based on his experience in Norway was discussed. His experience suggests that in Norway sea birds adjust to the presence of White-tailed eagle by moving their nest sites, for example Guillemots into denser colonies or inaccessible sites such as cave and fissures.  He also suggested that there would be no significant impact until 50 years after re-introduction.   Pembrokeshire is not comparable to the Norwegian situation. Our seabirds live on the very edge of their range, quite simply our birds will have nowhere to move to.  The papers presented suggest that the diet of White-tailed eagles will focus on whatever food source is seasonally abundant, and given the density of breeding populations of auks on the Islands, this raises particular concerns, particularly if the population of White-tailed eagles increased over time.

Academic members of ICAC were asked to comment on the re-introduction proposal, email responses were received from, Professor Stephen Votier, Professor Tim Birkhead, Professor Chris Perrins, Professor Tim Guilford, and Dr Matt Wood. Their unanimous response was that the introduction of White-tailed eagles would present a very high risk to seabirds in the future. Professor Votier noted:

“It is clear that WTE can have severe impacts on seabird populations – they seem especially vulnerable because eagle can indirectly effect social aspects of breeding. The Pembrokeshire seabird assemblage is hugely significant not just because of the number and range of species, but also because the trends of most taxa are upward, in contrast to many other areas. Therefore, reintroducing WTE would seem to present a very real risk to their long term future.”

The Skokholm Wardens commented: “The Pembrokeshire auk populations are not what they were when eagles toured the coast, and the populations of opportunistic egg/chick predators are likely higher. There were some disturbing tweets from Scandinavia this summer again implicating disturbance from eagles with colony collapse, although there are other issues there re. food availability. It would seem a big risk to introduce a higher than natural loading of eagles into such a sensitive area. “

Their comments confirmed our assertion that there is currently insufficient scientific evidence to support reintroduction. 

We also discussed the impact that the scheme could have on stakeholders, in particular our relationship with the farming communities. The ERW project recognises the likely intolerance of farmers in North Wales to a Sea Eagle reintroduction, but felt that Pembrokeshire farmers would be more tolerant because farming is less linked with lambs in this area. This issue is important because WTSWW must maintain as good a working relationship as possible with farmers and other members of local, rural communities. 

Conclusion

When we apply the precautionary principle and consider the potential impacts on seabirds in the short and longer term, and consider the IUCN and our guidelines on re-introduction, we have to conclude that WTSWW cannot support the reintroduction of White-tailed eagles to Pembrokeshire. 

Our view is that the scheme must not go ahead until there is sufficient scientific evidence to demonstrate, beyond any reasonable doubt, that there will be no adverse effect on the seabird populations. This evidence will be needed for the proposal to go pass through the EIA and HRA processes. We do not believe that there is sufficient evidence for this to happen or that any suitable compensatory measures for seabird impacts would be acceptable 

We strongly recommend that the Durrell Trust seek other areas in Wales which are much less environmentally sensitive and where there is no risk to existing important species and habitats.

We want to avoid public conflict with another conservation organisation, it is very important that we work together to achieve our common purposes. Unfortunately in this instance we are so desperately concerned with the risk to the seabirds that if an application is made to licence this operation, we will be obliged to contest the application.