South Stack Cliffs RSPB reserve is a nature reserve, run by the RSPB, on Holy Island on the North West coast of Anglesey, Wales.
The reserve is on sea cliffs facing the islet of South Stack, and is crossed by the Anglesey Coastal Path.
It is best known for its breeding seabirds, including puffins, razorbills, guillemots, kittiwakes and fulmars.
peregrine falcons, common kestrels and choughs also nest on the cliffs.
The area is famous for its rare bird species, such as black lark and grey catbird and fascinating geology.