It is during the winter that the swans give most character to the area. At the most, nearly 80 Song Swans have been seen here at one time. On the sea, the song swans like to graze on the eelgrass, but it is somewhat uncertain which plants the swans on the freshwater Tjeldstømarka eat. Early in the 1980s, a pair built a nest, but the nest was abandoned before any eggs were laid. Freshwater so far out on the coast seldom freezes. When it does, the swans must move. Then, they tend to head for the coast, with the embayment south on Skogsøyna as a much sought-after refuge. Some of the birds fly occasionally also to Lake Skulehusvatnet in Fjell. Large, heavy birds such as these are vulnerable when they fly. Every winter, several swans collide with power lines in Hordaland - also in Øygarden.
In the spring, flocks of Grey Goose often rest in Tjeldstømarka, and in recent years the nesting population has increased substantially. Roughly 10 pairs of goose nested in the area in 2004. Several types of duck make their permanent residence here, and there are wading birds such as the Lapwing, Oystercatcher, Red Shank and Snipe. The easiest to notice is nonetheless the Curlew, with its characteristic flight display. The Curlew is one of our biggest waders, easy to recognize with its long and downward-curving beak and long legs. Six-seven pairs nest in Tjeldstømarka. A number of years ago, the Ruff had its mating arena out on the bog during the spring migrations, but this has unfortunately come to an end. Out toward Hjeltefjord in the east, a pair of Arctic Skua have nested year after year, in fact as the only place in the county in our time.
In the bog one sees many old tree roots, as witness to that the area at one time was covered in forest. Tjeldstømarka is a combined nature preserve and cultural heritage area, and it was protected as a nature reserve in 1995. There are marked trails in the area, and a little hide for observing the birds is set up just on the east side of the highway.
