The Cuckoo—the Welch Ambassador

In Middleton’s *A Trick to Catch the Old One*, Act iv. sc. 5., Dampet says:— “Why, thou rogue of universality, do I not know thee? Thy sound is like the cuckoo, the Welch Embassador.” And the editor of the continuation of Dodsley’s *Collection* remarks on the passage,— “Why the cuckoo is called the Welch Embassador, I know not.” Perhaps some of your readers can explain why the cuckoo is so called.