Lying in the estuary of the River Teifi, it is known for having a small colony of grey seals.

In 1924 Welsh writer and naturalist Ronald Lockley wrote that there were probably 25 to 30 pairs on the island.

However, in 1934 the liner Herefordshire, being towed to the breakers' yard,[1] ran aground on the island in a storm, and rats made it ashore.

Over a period of years they ate the eggs and chicks of nesting seabirds, and wiped out the island’s population of puffin and Manx shearwater, which have never returned.

[3] Today, birds such as guillemots, razorbills, cormorants, shags, fulmars and a variety of sea-gulls all nest on the island.