Roofvogels en Boommarters Martes martes in de duinen bij Castricum in 2015

In 2015, members of the local raptor group discovered Pine Martens Martes martes on three nests of Buzzards Buteo buteo in the dunes near Castricum, indicative of the colonisation of the dunes by martens, and their subsequent increase. In this study area, many breeding territories of raptors now remain unoccupied, although some Buzzard pairs still breed close to a den of a Pine Marten. Other Buzzard pairs seem to prefer nesting sites without Pine Martens in the vicinity. Webcam observations in Friesland (V.S. van Bergen & R. Riem Vis) suggest that adult Buzzards are quite able to protect their eggs and young from Pine Martens, provided the nest is constantly guarded by one of the adults. In 2015, in the dunes near Castricum predation by a Pine Marten may have resulted in nest failure in a Buzzard, a Goshawk Accipiter gentilis and a Sparrowhawk Accipiter nisus. Other raptors may profit from predation by Pine Martens: in 2015, a Honey Buzzard Pernis apivorus – and perhaps even a Sparrowhawk – raised chicks successfully on nests possibly predated by Pine Martens a couple of weeks before.