The "Werkgroep Roofvogels Hoeksche Waard Oost" (= Working group birds of prey
Hoeksche Waard East) monitors the breeding population of birds of prey in the
eastern half of 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 15000Ha.
The monitored raptor species are: Common Buzzard (Buteo buteo), Goshawk (Accipiter Gentilis),
Sparrowhawk (Accipiter Nisus), Kestrel (Falco Tinnunculus), Hobby (Falco Subbuteo) 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 15-20, 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
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 band 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 35-50 pairs of common buzzard, 4-8 pairs of Goshawk, 6-13 Sparrowhawk, 3-5
hobby, 0-3 Peregrine pairs and 9-27 pairs of kestrel (numbers more or less corrected for
changing methods and changing working area).
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 2011 this resulted in
finding 13 breeding and 2 territorial pairs. Dutch peregrines are banded with special
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.