The main breeding areas are located on the lower peat soils in the northwest half of the country. The breeding area has somewhat contracted (except for the core areas) compared to the 1970s. Census results suggest an increase up to about 1980, followed by a slight decrease afterwards. However, local trends may be conflicting. Common Pochards apparently did nog benefit from improved water quality and recovery of aquatic vegetations. Stagnation in breeding numbers (1700-2100 bp in 1998-2000, clearly more than the 1000-1300 in 1973-77, but at the same level as in 1979-85) contrasts with the continuing increase of Tufted Duck.