Just off Caldey’s western tip, across a narrow channel called Little Sound, lies St Margaret’s Island, a low seven hectares once known as Little Caldey. You can’t land: the Wildlife Trust of South and West Wales, which has managed the island as a nature reserve since 1950, allows no public access at all. Cormorants nest on the cliffs in the largest colony of the bird in Wales, alongside guillemots, razorbills, shags and kittiwakes; puffins hang on in rock crevices, though rats on the island have pushed most of them out of their usual burrows.
Round-island boat trips from Tenby pass close by, the best way to see the seabirds and the grey seals resting on the rocks below. Caldey itself, a separate boat ride from Tenby harbour, does allow landing, with its village, abbey and priory ruins.
