West Mouse (Welsh: Maen y Bugail) is an islet lying 1.1 kilometres (0.68 mi) off the north-west coast of Anglesey, Wales.
The area also host to species such as hornwrack, sea squirts and conger eels.
The island is part of a set of three spread out along the north coast of Anglesey.
The Welsh name Maen y Bugail translates into English as The Shepherd's Stone.
He took the stone out and threw it into the Irish Sea, the island arising at the place in which it landed.