
The Welsh word for owl is tylluan and the plural is tylluanod. This word is used across Wales in all dialects.
Tylluan – Tylluanod
Owl – Owls
The word makes its earliest appearance in the Llyfr Gwyn Rhydderch (the White Book of Rhydderch), a significant 14th-century manuscript that holds a collection of Welsh legends known as the Mabinogi.