Before the wreck, Cardigan Island had been famous for them. A guidebook in the 1890s called the puffins "Welsh parrots", a name that captures something of their absurd, painted-clown faces and the noisy disorder of a thriving colony. In 1924 the Welsh naturalist Ronald Lockley counted roughly 25 to 30 pairs nesting in the burrows on the island's grassy crown. Manx shearwaters came in at dusk, navigating by smell back to nest holes they had used for years. The island, 52 metres at its highest point and only 38 acres in total, was big enough to feel oceanic from a kayak but small enough that a single bad night could change its biology forever.

The Herefordshire was a Bibby Line ocean liner of nearly 8,000 tons, decommissioned and being towed from the Mersey to a Welsh scrapyard when the weather turned. Her tow parted in heavy seas off Ceredigion, and she drifted onto Cardigan Island, where she broke up against the cliffs. The wreck still draws divers; marine life has colonised the iron and made it a small reef. But the rats that came ashore in 1934 had no such useful role. They worked through the burrows methodically, year after year, and the seabirds that depended on island isolation discovered that the isolation had ended.

Forty-five years is a long time to fight a small mammal on a small island. The Wildlife Trust of South and West Wales, which owns Cardigan Island, only managed to declare the rats gone in the late 1970s. By then the puffin colony was generations vanished. Shearwaters did not return. What did return, slowly, was everything else: guillemots, razorbills, cormorants, shags, fulmars, and the usual Welsh assembly of gulls now nest on the cliff ledges where mammals cannot easily reach. A small flock of Soay sheep grazes the grass, descendants of an experiment in keeping the vegetation low enough for ground-nesting species that might one day come back.

From the coast at Gwbert, Cardigan Island looks impossibly close — barely 200 metres of churning channel separates it from the mainland. The strip of water is what saves it. Atlantic grey seals haul out on its rocks and pup in its sea caves. Bottlenose dolphins from Cardigan Bay's resident population, one of only two such colonies in British waters, pass between the island and the headland on most calm summer days. Watching from the clifftop path, the eye moves naturally from seal to seal, then catches the sudden dark arc of a dolphin's back, and then realises that the bird wheeling above the waves is a chough — red beak, glossy black, a survivor of older Welsh skies.

Cardigan Island is a small lesson in how easily a place can be unmade. A snapped tow rope, a few rats, and a colony that had been there long enough to earn a nickname was simply gone. The Wildlife Trust now treats the island the way a museum treats an irreplaceable manuscript: with constant vigilance, monitored visits, and careful biosecurity for anyone who lands on it. Recovery is slow and uncertain. The cliffs are louder than they were in the lean years, the seals are back in numbers, the dolphins still come. But the burrows on the island's grassy top stay empty, and the Welsh parrots, for now, remain a memory carried only in old guidebooks.