Lutra 58(2)_Bekker et al_2015

A review of the results obtained during the Field Study Group summer camps of the Dutch Mammal Society, 1986-2014

The 28 summer camps of the Field Study Group of the Dutch Mammal Society organised between 1986 and 2014 are reviewed here. Over time the Field Study Group gradually spread out its activities throughout Europe, including former Eastern Bloc countries. Camp locations were found through contacts in host countries, who also assist in the preparation of camp activities. Out of a total of 160 participants from the Netherlands and Belgium, 80 attended a summer camp once and 80 joined more than once; 116 participants from local origin were active during these camps. For the 128 mammal species found, the observation techniques used are described. Overall, 7,662 small mammals were caught with live-traps and 990 bats were caught in mist nets. Among the trapped mammals, 421 casualties were counted, predominantly common and pygmy shrews in northern European countries. In pellets, predominantly from barn owls, 21,620 small mammals were found. With detectors, 3,908 bats could be identified. Caves and (old) buildings were explored for bats, and the results of these surveys made up a large part of the total number of bats found. Sightings (> 1,740) and tracks & signs (> 1,194) revealed most of all the presence of carnivora and even-toed ungulates (Artiodactyla). Since 2007, infrared camera traps were used to detect medium-sized and larger mammals; 77 individuals were detected with this relatively new technique. During seven camps, parasites were taken from 23 bat species: most of these were mites (80%) and louse flies (Diptera: Hippoboscidae) (15%). The locations where mammal species were found were compared to the existing knowledge (expressed as presence in 50x50 km UTM grid squares) on the distribution of mammal species in Europe, as presented in The Atlas of European mammals by Mitchell-Jones et al. (1999). The presence of mammal species was confirmed in 1,268 squares; 35 squares reaffirmed their presence after 1970, and in 218 new squares an extension of the distribution was demonstrated for a number of mammal species. The highest proportion of new squares appeared to be for Chiroptera, mostly due to the use of mist nets and the introduction of bat detectors as a new technique. Besides positive mammal observations, attention has also been paid to species that, against all odds, were not observed in specific areas. The application of newly introduced, tested, techniques during the study period are part of this review.