Blackbird of Cilgwri
An ancient bird with whom Gwrhyr the Interpreter communicated during the expedition mounted to help Culhwch locate the maiden Olwen.
The bird directed them to the Stag of Rhedynfrc, which in turn sent them to the Owl of Cwn Cawlwyd, which took them to the Eagle of Gwernabwy, which guided them to the Salmon of Llyn Llw.