Along with the day to day wardening tasks that are required to look after one of the south coasts largest seabirds colonies, each summer we like to trial one or two innovative solutions to some of the conservation issues being faced here. This year, with the help of some amazing RSPB volunteers, we put together something I've been thinking about for a while now that I'm (perhaps optimistically) calling, a 'tern table'..
The Langstone Harbour RSPB reserve covers an impressive 554 hectares in the north of the Harbour. Although a vast area, virtually all of this is intertidal mud or open water. The area of shingle that remains safe above high tide covers just 1 hectare and it's here that the overwhelming majority of shorebirds breed. There is however another component to the mosaic that mostly stays above water and that's the 70 wonderful hectares of saltmarsh.
Above: Saltmarsh in the Langstone and Chichester Harbours Special Protection Area.
Saltmarsh is a rich coastal habitat full of meandering channels, vegetated plains and a bounty of life between land and sea. In the past, the saltmarsh islands here acted as another shorebird colony site but increasingly, nesting attempts have ended in flooding as the marshes slip beneath the waves of boosted spring tides. Located away from the intense competition of the main seabird colony, small areas of shingle on the saltmarsh edge here have formerly acted as attractive nesting sites for common and little terns as well as Oystercatchers and Ringed plover. Restoring this function could have a great impact for these species but raising the height of these areas would be a massive logistical undertaking. What we needed was a way of creating a temporary, heightened area that would be attractive to shorebirds but also within the ability of a small team to deliver. Taking lessons on board from the nesting raft project nearby on Hayling Island, we thought we'd try something novel and erect a shorebird nesting platform on the marsh edge. Essentially it would just be a shingle covered deck or platform high enough to keep it above the surging spring tides. Would it work? I really didn't know how it was going to plan out but as doing nothing would surely result in a negative outcome, plans were put into place, permissions were granted and it was soon time to find out.
With a packed work program, it was late May before we were able to finally build the nesting platform (or 'tern table' as it was now being called). By this point, the major colonies of all seabird species within the harbour had formed but there was still plenty of time for later nesting birds to set up. Over the course of two days, the large wooden frame and decking of the platform were bought out on the reserve boat, 'The Good Tern' and bolted together near the edge of a secluded marsh island that terns had been observed feeding near. Standing just over a metre in height, the platform easily rose above the spring tide lines. To prevent any damage to the marsh, the wooden legs stood on top of rectangular weight spreading "feet" (rather than being dug in) and were secured to gabion baskets filled with large shingle pieces as an added security. On top, a 2m x 2m area of shingle and crushed oyster shells were surrounded by a small perimeter fence (to stop any chicks falling off soon after hatching). As a final finishing touch, a few hand made common tern decoys were added for social attraction.
Above: Our floating workhorse, "The Good Tern" serving us well as always.
Above: Thank you guys! We couldn't have done a thing without our amazing volunteers.
Above: In need of some friends, common tern decoys in place..
Above: The fished product, "Tern Table 01" with....an Oystercatcher!
We didn't have to wait for long to find out what would happen and although we didn't get any terns nesting, the result was a good one. Within just 48 hours of erecting the platform and leaving it in peace and quiet, a pair of Oystercatcher were incubating a clutch of eggs in it's center and 27 days later they successfully hatched three chicks. The chicks were recorded on camera for the first week giving us a great opportunity to see their chick rearing habits in detail and, although we can't be 100% certain due to how mobile they become before fledgling, there's a good chance that at least one of these youngsters were recorded again within the local area with their parents a month later.
Above: The adult Oystercatcher removing the eggshell as soon as a chick has hatched.
Above: Finding their feet, newly hatched chicks.
Above: A small flock of starlings come to visit.
Above: Time to snuggle back under the wing.
It's been an interesting side project on the reserve this year but there's still some development to go. The height can be lowered by about a third of a metre comfortably and this should make it more attractive. Starting earlier next year, we'll be modifying the design to build in a few changes and then getting things ready (along with everything else) for the spring influx of breeding shorebirds. With a mostly static coastline and rising seas, we may very well be needing innovative solutions to shorebird habitat in the coming years and little projects like this might just help inform the bigger picture of what's possible. Tern table 2.0 is on the way.