Rallus aquaticus – RHEGAN Y DWR – Winter visitor and scarce breeder
The BTO winter atlas showed that Water rails were present in the majority of 10km squares during the winters of 1981-82, 1982-82 and 1983-84.
The darker the colour, the higher the relative total count for each 10km square. The darkest blue represents over 3 birds seen in a day.
To a large degree the plotted distribution follows the degree of observer effort.
Data collected by volunteers for the BTO. Lack, P. 1986 Atlas of wintering birds in Britain and Ireland. T & A.D. Poyser.