Tadorna tadorna – HWYADEN YR EITHIN – Breeding resident and winter visitor
The BTO winter atlas showed that Shelducks were predominantly present in estuarine 10km squares during the winters of 1981-82, 1982-82 and 1983-84.
The darkest colour in a 10km square represents over 81 birds seen in a day.
Graham Rees. Pembrokeshire County Bird Recorder 1981-2007
Data collected by volunteers for the BTO. Lack, P. 1986 Atlas of wintering birds in Britain and Ireland. T & A.D. Poyser.