We can thank the plans for the power station for helping us to learn so much about the animal life in the valley. In connection with the application by Haugesund Energy company’s application to build out into the Stordal Valley water system, a comprehensive investigation was carried out in 1984. What was discovered about the animal life resulted in the building plans being replaced by permanent protection for the animals.
Lake Stordal, the biggest lake in Sunnhordland, lies considerably lower than the highest sea level after the last Ice Age (75-80 metres over sea level), a so-called fjord-lake. That is to say that the water had previously been a fjord, that turned into a lake as the land rose. Lake Stordal is rich in fish, with six types suitable for fishing: salmon, seatrout, trout, eel, stickleback, and char. Char is especially plentiful. The abundance of fish makes the lake very good feeding grounds for the arctic loon in summer, and for the goosander (also called merganser), the red-breasted merganser, grey heron and others in winter. In recent years there has also been a pair of White-winged scooters nesting here, which is extremely unusual in southern Norway. Because of the calcium-rich bedrock, together with the seepage from agriculture, the water can tolerate acidic rainfall. The many different species have therefore managed quite well.
The nearest drainage basin is dominated by an open cultivated forest, many places with a row of ancient, cropped (“pollarded”) deciduous trees that create good conditions for a varied bird life. One reckons that there are 6-8 nesting pairs of the County Bird, the White-backed woodpecker, in the river system, and there are good populations of the lesser spotted woodpecker (see picture to left). This is a sign of good availability of nutrients, especially of insect species that are typical of dead or dying timber. The cultivated forest also has abundant tits, black and white woodpeckers and cat owls.
The grey alder forest in Stordalen has attracted special interest. In an area by Hellaug one finds an average of 1120 bird pairs per square kilometre. This is the most recorded anywhere in Norway, regardless of forest type.