The same word corr was used in Irish to describe both the Crane and the Heron. For example, some early Irish legends associate the heron with St Colmcille ( or Columbia). A story about Colmcille, which appears in Geoffrey Keating’s History Of Ireland, concerns how he turned a queen and her handmaid into herons in retaliation to their lack of hospitality. According the the story Colmcille arrived in Ireland from Scotland to attend the convention of Drum Ceat hosted by King Aodh. Aodh’s wife told her son Conall not to show any reference to ‘crane-cleric’ or his company and in retaliation the saint turned the queen and her handmaid ( who conveyed the news) into herons. The two herons were fated to stay on the ford of Drum Ceat until Doom, and it is further said that, ever since then, the two birds can be seen at the ford.
Information taken from: Niall Mac Coiter’s, Irelands Birds Myths, Legends And Folklore.