Haematopus ostralegus
Mathew mentions breeding only on the Bishop's Rock and Skomer, also on "a small island at the entrance to Milford Haven". Now apparently much increased, especially Skokholm (over 50 pairs 1947 and 1948). Breeding round all coasts and on all islands, including South Bishop and Grassholm.
R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society