Range of Movement and Activity of Common Rats (Rattus norvegicus) on Agricultural Land

Abstract

(1) Radio-tracking techniques were used to study movements of rats on arable land. The mean range length for ten female rats was 340 m and for seven male rats 660 m. (2) Movement occurred primarily along hedgerows which provided cover, but several individuals occasionally crossed open ground, covering distances of up to 500 m without approaching cover. Most of the movements observed were between homesites and known food sources up to 500 m away. (3) Although the rats frequently changed their homesites, there was no noticeable tendency to move them towards recognized food sources in the area; changes of homesite were apparently random occurrences or were related to encounters with other rats. Males and females changed their homesites on average once every 7 and 14 days respectively. (4) The rats studied became active soon after sunset but generally did not move away from their homes until about one hour later. Peak activity occurred 4-5 h after sunset. Six of the twenty-one rats studied were active at times during daylight and one was predominantly diurnal. (5) Eleven rats with transmitters died during the experiment including five that were killed by predators. (6) The failure of outdoor rats to become established in farm buildings, despite apparent food shortage. in the fields, is attributed to antagonism from rats already resident in the buildings.