The BTO winter atlas showed that Teals 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 150 birds seen in a day.
The map demonstrates the variation between numbers of National Importance at the Cleddau Estuary and the occurrence of two or three birds on small ponds.
Graham Rees