With the aid of a trapping techniques with tins (one tin to the square meter) carabid beetles were collected at Schiermonnikoog, one of the Wadden-islands, in 1958, 1959 and 1960. Calathus melanocephalus was most active at the beginning of the nocturnal period. The number of animals which were caught in different nights is related to the temperature. The higher temperature in the nocturnal period, the more animals are trapped. The animals in some periods prefer a very dense vegetation as LINDROTH (1945) has remarked; at other times (as LARSSON, 1939, noted), a scarce vegetation. This is most probably related to the amount of rainfall. In dryer periods Calathus melanocephalus prefers dense vegetation, whereas in periods with a good amount of rainfall areas with scarce vegetation are preferred.