Skomer Island Manx Shearwater
The Manx shearwater is 30–38 cm (12–15 in) with a 76–89 cm (30–35 in) wingspan and weighs 350–575 g (12.3–20.3 oz). It has the typically "shearing" flight of the genus, dipping from side to side on stiff wings with few wingbeats, the wing tips almost touching the water. This bird looks like a flying cross, with its wings held at right angles to the body, and it changes from black to white as the black upper parts and white under sides are alternately exposed as it travels low over the sea.
