The study was conducted in Vinh Phuc Province, in northern Vietnam, 40 km north of Hanoi (21°08’ N; 105°45’ E). Four study sites were selected to comprise part of a main village or sub-villages. Each site was 0.5 to 1 km apart and about 100 - 150 ha in size. The sites were set up in March 1999 to monitor the population dynamics of rats before implementation of ecologically based rodent management (BROWN et al., 2003b). Within each