The "Werkgroep Roofvogels Hoeksche Waard" (= Working group birds of prey Hoeksche Waard) monitors the breeding population of birds of prey in the Hoeksche Waard since 2000. The Hoeksche Waard is a polder a few kilometers south of Rotterdam, the Netherlands. It is mostly open agricultural country with some towns and industry and some (very) small patches of bushes and woods. The Hoeksche Waard is divided by the north-south highway A29, the eastern half is about 158Km2, the western half 106Km2. English Summary
The monitored raptor species are: Common Buzzard (Buteo buteo), Goshawk (Accipiter Gentilis), Sparrowhawk (Accipiter Nisus), Kestrel (Falco Tinnunculus), Hobby (Falco Subbuteo), White-tailed eagle (Haliaeetus Albicilla), Honey Buzzard (Pernis Apivorus) and a few pairs of peregrine falcon (Falco Peregrinus) .
Also breeding in our working area are a number of Marsh Harriers (Circus Aeruginosus), probably around 40-50 pairs, but they are not monitored 'cause of lack of manpower.
Sometimes we "assist" the birds by providing nestboxes and always we try to keep a watchful eye to detect possible bird-of-prey persecution, like on-purpose nest disturbances or poisoning.
Monitoring consists of determining active territorial pairs (pairs who at least show some repeating interest in starting a nest). Keeping track of their breeding success, by nest inspections from the ground, by camera on a pole and by climbing to the nest. If we climb to a nest we try to weigh, measure and ring the young birds as well. We keep to stick to the methods described by Rob Bijlsma's book "Manual for raptor field-research" (in Dutch: "Handleiding veldonderzoek roofvogels", 1997).
To give an idea on the numbers we are talking: in the years we're monitoring the raptors we've seen 60-90 pairs of common buzzard, 8-15 pairs of Goshawk, 6-15 Sparrowhawk, 3-5 hobby, 0-4 Peregrine pairs and 9-35 pairs of kestrel (numbers more or less corrected for changing methods and changing working area).Since 2019 a pair of White-taied eagles started breeding in the westmost point of the Hoeksche Waard. Recently (2025) there are clear signs of a succesfull Honey-buzzard pair.
The populations are roughly stable except for the kestrel, which is fluctuating heavily sometimes, problably due to changing vole population.
Starting from 2010 we are also representing the "Werkgroup Slechtvalk Nederland" (= Dutch Peregrine Workgroup) in the provence of Zuid-Holland. In 2021 this resulted in finding 40+ breeding pairs. After that it went downhill due to HPAI. Dutch peregrines are banded with special colour-bands.
Due to the local character of this information translating the whole website into English doesn't seem very useful at this moment. If anyone wants more information in English they can mail to me.
Unless otherwise specified, all photo's and all texts: Martin Mollet
My photo's and texts may be used for non-commercial purposes.
Naming www.roofvogels-hw.nl as the source is strongly appreciated.
A mail to inform me about the usage too.
