Pticha Dupka Cave

The Pticha Dupka (Bird Hole) cave is situated in the Eastern Troyan Balkan. Its entrances are to the north of the site of Radya trap, but unfortunately there are no significat signs to find them. The local people know where the entrances are located long ago. The above-situated one is easier for descending. Its altitude is 1260 m. The length of the initial plummet is 65 m and downwards it becomes wider and reaches 10 m of diameter. The actual bottom of the cave is situated lower and could be reached without a rope. There is a small stream and two galleries go in opposite directions – upwards and downwards. The main color of its walls is reddish. Overcoming plenty of blocks, two small vertical passages and one magnificent sinter lake the visitor reaches a hall about 30 m in length. The abundance and variety of the formations here is extraordinary – cave pearls in small sinter cavities and lakes are seen as well as long, thin and carrot like stalactites, stalagmites, stalactones, rich draperies and stone waterfalls could be seen all around. Here is the deepest point of the cave – 108 m where the underground stream disappears in a siphon amidst fallen from the ceiling blocks. The total length of the descending gallery is 302 m.

The total length of Pticha Dupka is 652 m and its depth is 108 m. The name of the cave comes from the fact that there is a colony of alpine chows inhabiting it. Their nests are placed along the walls of the main vertical passage and the birds create their nests in almost no sun light. Other dwellers of the cave are the troglobiont snail Spinophallus uminskii and troglobiont shrimp Niphargus bureschi and the millipede Anamastigona alba is endemic for Pticha Dupka and Kumanitsa. Spiders, harvestmen and beetles also inhabit the cave.