The BTO winter atlas showed that Common Gulls were present in most 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 up to 400 birds in a day.
Found extensively using wet pasture and newly ploughed land but all roosts reported were around the estuaries.
Graham Rees