Many spruce trees in the national park are old and have been attacked by honey fungus, which weakens trees.
The fungus-afflicted trees subsequently become habitat for bark beetles and other insects that live in wood. They then constitute a pantry for many birds, including the three-toed woodpecker. As early as March, the visitor is greeted by the first flower, the daphne, which produces violet blossoms on a bare sprig. Some weeks later it is followed by thousands of hepaticas and wood anemones. By this time many migratory fowl have arrived, including song thrushes, chaffinches, European robins and hawfinches. In May the avian chorus is taken over by songbirds such as the blackcap and wood warbler.