Cornwall ’s national bird has returned to a medieval castle in the county for the first time in decades in a moment heralded by birdwatchers and mythology fans alike. Choughs, with their red feet and bills, appear on the Cornish coat of arms in a symbol of their importance to the county. But they vanished from the county altogether more than 50 years ago because of the decline of their grazed clifftop habitat. Now, they have been spotted for the first time at Tintagel Castle – a place they are strongly connected with through the Arthurian legend. King Arthur was said to have been conceived at Tintagel and Cornish legend stipulates that he didn’t die after his final battle, but instead turned into a chough. Killing the chough was believed to be unlucky because of this legend.…