Blog post by Chantal MacLeod-Nolan, Project Assistant, Roseate Tern LIFE project.
The history of roseate terns in the British Isles has been a rocky one.
With their plumage prized for fashionable hats, this almost caused them to become extinct in the 19th Century. Although the creation of wildlife laws protected them, by the end of 1970s they had suffered another population crash with only 467 pairs remaining in 1989.
Through the long-term efforts of active conservation at the remaining three colonies, the roseate tern population has been steadily increasing since 1989, reaching a record level of 1980 pairs in 2018.
As in previous years, the growth was mostly driven by Rockabill (Ireland) with 1633 pairs recorded, but also Lady’s Island Lake (IRL) with 227 pairs and Coquet (UK) – 118 pairs. The productivity on Rockabill has been declining in recent years, reaching a record low level of 0.66 chicks per pair in 2016 and only slightly better 0.83 last year.
On the other hand, Coquet had an exceptional productivity of 1.50 chicks per pair in 2017.
The project
2018 also marked the third year of the Roseate Tern LIFE Project, which is a partnership between the RSPB, BirdWatch Ireland and North Wales Wildlife Trust.
The project focuses on enhancing breeding conditions at the core colonies in Ireland and the UK, while also improving five former roseate tern SPAs in preparation for a potential expansion. As roseate terns rarely breed on their own, it is essential to improve the breeding conditions for common, Arctic and Sandwich terns at their former nesting sites.
Map showing sites where the project is working
The funds from the LIFE project have enabled partners to increase wardening hours, clear vegetation, create more terraces and increase the number of nest boxes.
Roseate terns, unlike other terns, prefer to nest in crevices. As a result, they readily use nest boxes, which protect chicks from the elements and predators.
Wardens have also been able to discourage large gulls from occupying and predating nesting sites through trialling new techniques including gull scarers and Agrilasers (laser technology to deter birds). Biosecurity measures and exclusion fencing was also implemented across certain colonies to deter mammalian predators.
What's happening at other sites?
Additional efforts have also been made to restore the sites in Western Solent. Here, tern habitat has degraded predominantly due to erosion and subsequent flooding, which creates added pressure for nesting space. This has included a shingle recharge to the eroding cheniers (saltmarsh ridges), three nesting bunds on a breakwater and the deploying of tern rafts.
Another aspect also involves restoring tern islands which support nationally important colonies of common and Sandwich terns at Cemlyn Bay and Larne Lough. Once the constructions are completed, both sites will be able to better support expanding tern colonies.
This year we are pleased to announce that two roseate terns successfully fledged from the Skerries for the first time in 12 years, attributed to the staff efforts in managing the breeding seabird population on the island including the UK’s largest Arctic tern colony and we are optimistic of attracting more terns in the future.
Roseate terns using nest boxes
Research
The LIFE project is also leading on several key areas of research including a demography study, which revealed that the population growth at Coquet Island has been driven on immigration from Rockabill, whereas the growth of Irish colonies is driven more by productivity and the survival of juveniles/adults.
Sandeel and alternative prey species reviews led to the development of prey hotspot areas for future management. Analyses of a 25-year Arctic tern diet dataset from Anglesey have shown an increased intake of clupeids (sprat/ herring) in recent years compared to a previously sandeel-dominated diet.
Additionally, the wintering hotspots in Ghana were surveyed and illegal tern trapping is confirmed to still be ongoing in places. Geolocators have also been deployed to understand roseate tern migration patterns.
What's next?
All of this research reinforces the importance of collaboration between other organisations managing the Western European metapopulation of roseate terns. The Project team has visited the two remaining European colonies in France and the Azores, which has increased the understanding and encouraged information exchange across countries.
Towards the end of the LIFE Project (2020), the International Roseate Tern Conservation Strategy will be updated, underpinned by development and sharing of best practice.
For more information, please visit the project website or follow us on Twitter.