This dataset contains the results of the yearly summer camp of the Field Study Group (Dutch Mammal Society), organized from July 29th to August 7th 2008 in the Muntii Pădurea Craiului , the lower part of the Apuseni mountains, Romania. The mammals of the Muntii Pădurea Craiului and its surroundings were the main object of study, using various methods. Live traps and small batches of owl pellets were used to identify small mammals like shrews and mice. Data on bats was gathered with bat detectors and mistnets. Bat parasites and DNA material were collected from all bats captured and identified afterwards. Other mammal species were observed visually or by use of camera and video monitors. While recording mammals, attention was given to insects (butterflies, dragonflies and grasshoppers), amphibians, reptiles and birds as well. Locations were recorded with GPS.