This dataset contains the results of the yearly summer camp of the Field Study Group (Dutch Mammal Society), organized from July 17th to July 27th 2007 in Matsalu Rahvuspark (Matsalu National Park), Estonia. The mammals of Matsalu 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, mistnets and harp traps. 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. ...