Scilly's Nature Designations SSSI's Pentle Bay, Merrick and Round Islands Size: 4.6 hectares % of total area of SSSI's: 1.13% Designated features: Common Tern, Roseate Tern, Storm Petrel General Description Pentle Bay off Tresco forms part of a larger SSSI complex, which includes several offshore islands including Merrick and Round Islands. Of this complex SSSI the Trust manages the offshore islands only, whilst Pentle Bay falls under the management of Tresco Estate. These offshore islands are particularly important for the breeding seabird colonies, in particular Round Island where Storm Petrel are known to breed. The other offshore islands have also been historically important for breeding seabirds particularly Roseate Tern and Common Tern, the latter also known to nest within the lichen-rich heathland of Appletree Banks SSSI on Tresco (also managed by Tresco Estate) Practical Management As with all the offshore uninhabited islands non-intervention is key to ensure that our seabirds can breed with minimum disturbance. However, there are continuing declines in seabird numbers which are in part due to climate change, which has resulted in more frequent storms that over-top the islands on which the birds breed. Along with changes in food availability due to increased temperatures in the sea, a drop of almost 90% in the number of breeding Common Terns and a complete loss of Roseate Tern in Scilly has occurred.