He continued his missionary work, travelling the breadth of the country from Berwick to Galloway to carry out pastoral work and founding an oratory at Dull, Scotland complete with a large stone cross, and a little cell for himself, at a site which subsequently became a monastery then later the University of St Andrews.
In 676 he adopted the solitary life and retired to a cave. After a time he settled on one of the Farne Islands, south of Lindisfarne, there he gave himself more and more to austerities. While on the Farne Islands, he instituted special laws to protect the Eider ducks and other seabirds nesting on the islands; these may have been the first bird protection laws anywhere in the world. Consequently, eider ducks are often called cuddy ducks (Cuthbert's ducks) in modern Northumbrian dialects.
In 684, at a synod at Twyford (believed to be present day Alnmoth) Cuthbert was elected bishop of Lindisfarne. It was only after a visit from king Ecgfrith, that he agreed to return and take up the duties of bishop. He was consecrated at York on 26 March 685.
After the Christmas of 686, he returned to his cell on Inner Farne Island (two miles from Bamburgh Northumberland), where he eventually died. He was buried at Lindisfarne.
living water reprint from 2009