The birdlife in Gribskov is varied and of international importance.
The forest is home to the largest populations of common goldeneye, green sandpiper and red-backed shrike in Denmark and near Nødebo at Lake Esrum, a noisy colony of great cormorants has found a home.
Tradition says the lake is bottomless and was created when God angrily punished a nunnery that once was here.There are several interesting bodies of water in Gribskov, seen both from a scientific and a folkloristic viewpoint: Store Gribsø (English: Large Grib-lake), or just Gribsø, is only a 10 ha lake, but is nevertheless the largest lake enclosed by Gribskov.It is a so-called dystrophic lake and it is impossible to see the bottom in its dark waters, even though it is only 11 m deep.Only a thin strip of Hillerød town in the south separates Gribskov from many larger woodlands such as Store Dyrehave at 1,100 ha, Tokkekøb Hegn at 631 ha and several smaller woods.but the actual meaning and etymology of the word go a bit deeper.
Moden dating Gribskov
'Grib' refers to the Old Danish word for something 'without any specific owner', so 'Gribskov' actually means a woodland of common ownership.On top of that, Gribskov is designated as an Important Bird Area (IBA). 1,200 ha of the forest has been reserved as 'forest to be untouched', in an effort to preserve some of the few spots of semi-natural woodland (SNW) in Denmark and stimulate the growth of new.There had been a long tradition of draining by digging ditches and regulating the natural waterflow in the forest for various reasons, but these practises have now ceased and work is in progress to re-establish a more natural waterflow and improved conditions for wetland areas.This already has enhanced biological diversity and has had a direct positive influence on the living conditions for birds in Gribskov.It is a 2–3 km long artificial canal, winding its way through the forest from the lake of Store Gribsø and south towards the settlement of Gadevang in the southeastern section.