Cilgwri, Kilgwr
In Culhwch and Olwen, the Ousel (thrush) of Kilgwri was the first animal whose assistance was sought by Arthur’s warriors in their quest to find Mabon, an imprisoned huntsman.
The mystic and wise animal Ousel of Kilgwri sent them on to the Stag of Rhedenfre.
Source
Culhwch and Olwen | Late 11th century