At Cemlyn on Anglesey's north coast a shingle ridge, Esgair Gemlyn, separates a brackish lagoon from the sea. The lagoon is a National Nature Reserve where North Wales Wildlife Trust wardens patrol the ridge while the terns are nesting. Sandwich, common and Arctic terns breed here in spring and summer, and the Trust counts the colony among Britain's largest nesting populations of Sandwich terns, best watched from the viewing area on the ridge. Sea kale, sea campion and yellow horned poppy grow on the shifting stones. Bryn Aber was home to Captain Vivian Hewitt, who in 1912, by the Trust's account, became the first man to fly across the Irish Sea. Three Trust trails of one, two and three miles start from the car park, covering the ridge, the Trwyn Cemlyn headland and Llanrhwydrus church. Dogs are welcome all year but must stay on a lead because of nesting birds. Reviewers rate Cemlyn for birdwatching and find it remote and uncrowded. The car park and the bridge to the ridge can flood at high tide, so check tide times before setting out.