The nature reserve Duivelsberg and other hills lies on a moraine. The hills are covered with forest with beech, oak and other trees. In between are small meadows and crop fields. In the valleys are mall brooks, in spring you can find along the brooks wood anemone and oxlip.
The hilly forests are the main atraction, as the forest is quit old many birds breed here. Black Woodpecker, Lesser Spotted Woodpecker, Middle Spotted Woodpecker, Great Spotted Woodpecker and Eurasian Green Woodpecker all breed. In winter and early spring you can hear Tawny Owl. During an early morning walk in spring and early summer you can see Firecrest, Goldcrest,Crested Tit, Marsh Tit, Eurasian Bullfinch, Hawfinch, European Honey-buzzard, Common Buzzard, Northern Goshawk, Eurasian Sparrowhawk, Wood Warbler and European Pied Flycatcher. In the eastern part there is a breeding colony of Grey Heron. Eurasian Eagle Owl has been seen and heard in the area.
The best place to start your walk is at restaurant De Duivelsberg. Parking is possible next to the restaurant and at the end of your walk you can finish here with a pancake or a glass of cold beer on the terrace...
The area is only accesible on foot, some hills are steep and some hills have stairs to go up or down.