Dankzij kreekprojecten neemt Bruine Kiekendief Circus aeruginosus in de Hoeksche Waard toe

In 2010 a census of the Marsh Harrier was undertaken in the polders of Hoeksche Waard (27.400 ha), situated in the northern part of the Dutch delta. The area is surrounded by rivers and former estuaries (where reedbeds and rough herbage provide suitable breeding habitat) and consists of farmland (mostly arable). Marsh Harriers have been known to breed in this region since at least the 1940s. In 1970, at the end of the pesticide era, only two pairs remained (one of which on Tiengemeten, where in 2010 12 females and 16 males were located). The species recovered quickly after the ban on persistent pesticides, reaching 13 pairs in 1977 and 30-35 pairs in 1997. In the latter year, two of the pairs were found breeding in the polders, the rest in former tidal marshes beyond the dikes. The survey of 2010 revealed 46-49 territories, of which 18-19 territories in inland polder sites (Table 1). The increase is linked to restoration projects targeted at creeks and farmland.