Newborough Warren near the village of Newborough is a large dune and beach system of 2269ha, approximately half of which is a conifer plantation. The whole of the site is a Site of special scientific interest and all of the site except the forestry is a National nature reserve.The site is bounded to the south-east by Afon Braint and to the north-west by the Afon Cefni. It includes Llanddwyn Bay and Malltraeth Bay, divided by Ynys Llanddwyn, and part of the Anglesey Coastal Path.GeomorphologyThere are large expanses of both active and fixed dunes, although many of the latter have been afforested, along with a freshwater lake, salt marsh and mudflats and a tidal island. The reserve contains an outstanding flora, interesting lichen and moss communities and a wealth of invertebrates. The intertidal mudflats and saltmarshes are important wintering grounds for waders and wildfowl regularly supporting over one per cent of the British population of pintail. Ynys yr Adar, near Ynys Llanddwyn, supports over one per cent of the British breeding population of cormorant.