A lush and bird-rich valley stretching into the part of Oslomarka known as Krokskogen, a mature coniferous forest made famous through traditional Norwegian folk tales stating it is inhabited by trolls. Deciduous woods dominate the lower parts of the valley. Here you may find Green and Lesser Spotted Woodpeckers, several species of warbler, Long-tailed Tit and Hawfinch. Along the stream Isielva Dipper, Grey Wagtail and Common Sandpiper breed. In the coniferous parts higher up in the valley sides, Hazel Grouse, Tengmalm’s Owl, Black and Three-toed Woodpeckers may be found. The picturesque pasture Kjaglienga two kilometres from the parking lot is a traditional site for Common Rosefinch in late spring and summer. Nocturnal walks up the valley in March often produce three species of owl.