Red-breasted Merganser - 1980s winter atlas

The BTO winter atlas showed that Red-breasted Mergansers were present in some coastal and all estuarine 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 6-18 birds.

Graham Rees