Happy chicks take a tern for the better

Sandwich tern chicks have survived on Brownsea Island this season, thanks to the vigilance of Dorset Wildlife Trust wardens. These graceful gull-like sea birds, with long pointed wings and deeply forked tails, come each year to nest on the lagoon.  After a poor breeding record in 2010, when only three chicks fledged successfully, Sandwich terns this year have fledged about thirty young. 

A watchful eye was kept by the wardens at the reserve to ward off predators that take the young chicks, the heron being one of the main offenders.  Dorset Wildlife Trust’s Brownsea Island Manager, Chris Thain, is responsible for the nature reserve covering around half of the National Trust owned island.  He said, “One expects a certain amount of predation, but we were determined to try to improve on last year, when so many chicks were lost.  We have been taking it in turns to sleep in the hide that overlooks the lagoon.  When we heard the alarm calls of the terns, a torch was enough to scare off an intruding heron.  This seems to have been effective and the numbers of terns fledging has improved.”

Other measures taken to protect the terns this year include fencing off one of the man-made nesting islands to prevent mammals, especially deer, from trampling the nests.  Although Brownsea is free of many mammal predators, it does have rats and the occasional otter.  Sandwich terns, which have amber status as birds of conservation concern, depend largely on nature reserves for breeding sites in the UK.  Following work to provide the right habitat for the terns by Dorset Wildlife Trust wardens and volunteers, the population has grown from only six pairs in the 1960s to the busy colony we see today. 

Common terns, recognisable by their red bills, also nest on the lagoon.  Early indications are that this has not been a good season for them, with only sixteen fledged so far.  Around 50 pairs have laid a second clutch of eggs, so final results are not yet available.  Both species of tern will leave Dorset at the end of the summer to spend the winter in Africa.

There are good views of all the birds from the Macdonald hide in the Dorset Wildlife Trust reserve.  The reserve is open daily, with access via regular boats from Sandbanks, Poole and Bournemouth. For more information visit www.dorsetwildlifetrust.org.uk/binr