In the area around Tidan you find lake Östen, which is a typical floodplain lake, nutricious and shallow. It is one of the most valuable bird lakes in the country, and a very important link in the chain of resting places for migratory birds. The beautiful landscape around the lake bears evidence from thousands of years of human activity, and here you can also find several ancient monuments and cultural sights. Lake Östen, together with the rivers Tidan and Ösan, has connected large parts of north and east Skaraborg. A lot of the findings that have been made in the area indicates a very rich district. On your visit here, do not miss the ancient monuments Kung Ranes hög and Askeberga ship cumulus, or the cultural reserve Vallby Sörgården.
In Lake Östen Nature Reserve, which was designated in 1994 and covers 1,423 hectares, you can see several different bird species. It is common to spot geese, swans, ducks and waders. When the ice disappears in spring, the lake is visited by large numbers of whooper swans. Also less common bird species have been seen at the lake, for example redshanks, spotted crakes and grasshopper warblers.
For birdwatchers, the best time of the year to visit the lake is March and April, when the ice is breaking up. From Logården, you can reach both the birdwatching tower and the platform, and for those with impaired mobility there is the option of driving a car all the way to the platform, where there is a small car park.
Lake Östen is a shallow plains clay lake with nutrient-rich water and rich vegetation. The fact that the lake receives an extensive supply of nutrients together with the fact that the lake's water level has been lowered a number of times has led to some overgrowing. Several of the water meadows around Lake Östen are kept cleared of brush, which favours many bird species. The streams Tidan and Ösan flow through the lake.
When cattle graze on the edge of the shore, and open vegetation-free zone is formed between the shore and the reed belt. This "blue border" is a highly productive environment, where young birds can easily find food.