Creating safe havens for nesting terns in the Firth of Forth

The Forth Islands SPA (Special Protected Area) used to be the main breeding area for roseate terns in Scotland, however due to increased predation, the loss of nesting habitat and the resulting competition for the remaining areas, they have not been recorded breeding at any of the islands (or in the rest of Scotland) since 2009.

Along with the loss of roseate terns, the presence of other tern species declined in the Forth Islands SPA, with currently only two common tern colonies remaining: Long Craig Island and the Isle of May. Although not within the SPA, there is also a common tern colony at Leith Docks.

Scottish Natural Heritage manages the Isle of May and recently they have invested a lot of effort to create tern nesting areas with some positive results. In 2017, Arctic terns increased with 832 pairs and there were 29 pairs of common terns. After an eight-year hiatus, Sandwich terns were recorded nesting in 2016 and 2017.

Sunset behind the Isle of May (Photo Credit: Chantal Macleod-Nolan)

Long Craig Island, managed by the Scottish Wildlife Trust, is the only site within the Forth Island SPA, where the LIFE Project is involved. In 2017, there were 165 pairs of common terns nesting there and in 2016, the wardens recorded a roseate tern and common tern hybrid pair.

One of the key objectives of the Project is to restore the five sites which have historically supported breeding roseate terns. Through improving and boosting the survival of the common tern colonies may result in roseate terns being more inclined to recolonise these areas in the future.

​As Long Craig Island has limited nesting space for terns as a result of spring high tides; the LIFE Project deployed a 64 square metre raft in Port Edgar Marina just 1.5 km away from the island to support the population. It replaces an old pontoon, which was the site of a common tern colony, but which was badly damaged in the winter storms of 2014/15. The new raft will provide the terns at Long Craig additional nesting place which is both safe from flooding and mammalian predators on the mainland.

Materials arrived at Port Edgar Marina...time to build a raft! (Photo Credit: Chris Knowles)

​The materials for the raft arrived to Port Edgar Marina and was subsequently assembled on the jetty as per design by KAMES. Overall, the raft took a full 3 days to build and install into its designated space.

The main frame of the raft is made of galvanised steel and the decking is supported on pressure treated, Scottish grown Douglas Fir timber beams and secured using stainless steel fixings. The decking is made of recycled polyethylene planks covered with a ground geomembrane.

Building the main frame with the 10 floats attached (Photo Credit: Chris Knowles)

For buoyancy, there are 10 floats, of which each are filled with 790 litres of expanded closed cell polyurethane and the raft has been anchored with 4 huge, 100 Kg self-embedding anchors on 40mm thick chains.

Adding the decking of recycled polyethylene planks (Photo Credit: Chris Knowles)

Almost ready....and into the water the raft goes! Special thanks go to the LIFE Programme of the European Union for their funding. (Photo Credit: Chris Knowles)

Hard-working staff from KAMES and Roseate Tern LIFE Project Manager share a quick toast - it floats! (Photo Credit: Chris Knowles)

Back to work with raft fully in the water. Undergoing the final checks before it gets taken out and anchored in a quiet part of the marina (Photo Credit: Chris Knowles)

Once in place, the surface of the raft was covered in over 1 tonne of mixed source crushed shells to replicate the tern’s natural habitat. A number of shelters were also added to provide tern chick’s opportunity to hide from the elements or avian predators.

There are also 8 concrete tern decoys which simulate nesting birds in order attract passing terns to the new nesting area. These have been placed following RSPB guidance.

Raft fully deployed and anchored with the crushed shells, decoys and chicks shelters added. All that is needed are the terns! (Photo Credit: Chris Knowles)

​The pontoon has been anchored in a quiet area of the marina, but is visible from the shore, so hopefully visitors will be able to enjoy watching baby terns through binoculars, maybe even as early as this summer!

So if you are in the area and see terns near the raft, please let us know!