Cygnus cygnus – ALARCH GOGLEDD – Scarce winter visitor and passage migrant
Whooper Swans were registered in one 10km square in Pembrokeshire for the BTO winter atlas during the winters of 1981-82, 1982-82 and 1983-84.
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.