Fulica atra atra
Mathew describes it as resident on the few large pools in the summer but not numerous, even in winter.
Breeds (1948) at Bosherston Pools, and three pools near St Davids (including Dowrog). A winter visitor in small numbers, except in severe weather when thousands appear on Milford Haven estuary (eg winter 1933-34 and 1946-47). Recorded occasionally Skokholm in autumn. One adult and a jvenile seen on the sea off Grassholm, 6 Aug 1933.