COMPARATIVE ECOLOGY OF THE WOOD MOUSE APODEMUS-SYLVATICUS IN 2 DIFFERING HABITATS

Densities, variations in body mass, sex ratios, breeding activities an d size of home-range were studied in wood mouse populations living in a woodland and a reed bed. In the reed bed population: 1. spring densi ties were lower, 2. body mass differed, and was lower in early autumn, and 3. home ranges were larger than in the woodland population. It is suggested that differences in food availability and quality strongly influenced the behaviour of the two populations; the main effect of th ese differences was that reed bed mice entered winter with a lower bod y mass and suffered higher winter mortality. The larger size of the ho me range in the reed bed suggests that mice living in a poor-food habi tat will enhance their survival by patrolling a wider area than in a r ich habitat.