Rallus aquaticus aquaticus
A passage migrant on the islands, having been recorded even from the Smalls lighthouse several times. Has bred on Skokholm, and H.A.Gilbert records that it has bred in the marsh between Tenby and Penally. Common in winter, from late August onwards. Mathew conisdered it bred, but gave no definite evidence; he described it as numerous in winter, and not less numerous in summer!
R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society