ONE of the UK's rarest seabirds, which nests on the River Blackwater, is on the verge of extinction because of climate change, according to experts from the RSPB.
The Royal Society for the Protection of Birds (RSPB) fears that little terns could become a victim as rising seas and increased coastal flooding squeezes the county's coastline, pushing the birds closer to the homes that line the estuary.
The RSPB, which has a base at Old Hall Marshes in Tollesbury, has launched a project to raise awareness about the birds and their nesting habits, to try to educate the public.
Alex Cooper, RSPB conservation officer for Essex, said: "The little terns are one of the most vulnerable species in the UK, and the most vulnerable of the tern species.
"They just need space to breed undisturbed so we are urging visitors to follow any directions and advice given on local signs and to avoid entering certain areas while the little terns are breeding.
"We need to make sure that they have the best chance of finding a suitable home."
Little terns lay their camouflaged eggs on shingle or gravel coasts meaning unsuspecting walkers can easily trample on them and they are also at risk from foxes and other predators.
They can grow up to 25cm long with a 41 to 47cm wingspan, weighing similar to a tennis ball, and are amber listed by Birds of Conservation Concern 2009 and protected under the Wildlife and Countryside Act 1981.
"We want to work together with local fishermen and residents to inform people of the terns," Mr Cooper told the Chronicle.
"Local communities and recreational users of the Blackwater estuary have a vital role to play in helping little terns cope."
The birds have just started returning to Essex during their yearly migration, travelling thousands of miles from their wintering sites off the south and west coasts of Africa, and will stay until September.
He estimates that 30 to 40 pairs of terns, which feed on small fish, nest on Mersea Island alone with other smaller islands on the estuary also being used by the birds.
They lay two to four eggs on the ground and like all white terns are defensive of their nests and young, and will attack intruders that threaten them.
Around the Essex coast the possibility of little terns finding suitable places to nest is restricted because of the sea walls constructed on top of their favoured nesting areas close to the water.
Little terns are restricted to fewer than 60 key sites around the UK with traditional colonies at South Gare on the Tees and Donna Nook in Lincolnshire already lost due to changes in the English coastline.
In Essex, several of the nesting sites are at risk during spring tides and are likely to be lost in the future as a result of the sea level rise.
Susan Rendell-Read, the RSPB's little tern project manager, said: "Little terns are just one example of a bird species affected by climate change.
"They need undisturbed sand and shingle beaches with a plentiful supply of small fish just offshore.
"These beaches can be quickly altered by rising seas and floods making them unsuitable for terns to nest."
