Page update: 01 January 2000

Pticha Dupka Cave (The Bird hole)

The vertical Pticha Dupka cave is situated in Eastern Troyan Balkan and could be called a "pearl" among the Troyan cave because of its exclusive beauty. Its entrances are to the north of the site of Radya trap, surrounded by forest and there are no special landmarks to find them. The alpine climber Encho Petkov made the first attempt to enter inside the cave in 1948. In 1958 Bulgarian and Polish cave divers reached the bottom but its research continues in 1962, 1972 and in 1975 the first geological description of the region and the cave was accomplished.

The total length of Pticha Dupka is 652 m and its depth is - 108 cm. The name of the cave comes from the fact that there is a colony of alpine chows inhabiting it. Their nests are situated along the walls of the long initial vertical passage and the birds raise their nests in scarce and even absent 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.