E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Welsh Ambassador (The).
The cuckoo. Logan, in his poem To the Cuckoo calls it the messenger of Spring; but the Welsh ambassador means that the bird announces the migration of Welsh labourers into England for summer employment.
Why, thou rogue of universality, do I not know thee? This sound is like the cuckoo, the Welshambassador.Dampet: A Trick to Catch the Old One, iv. 5.