The Behavioural Ecology of the Wood Mouse (Apodemus sylvaticus) in the Cereal Field Ecosystem.

Abstract

This thesis presents a study of the behaviour and ecology of the European wood mouse (Apodemus sylvaticus) inhabiting the intensively farmed, cereal ecosystem of lowland Britain. The primary objectives were to ascertain how individual wood mice utilise the cereal field habitat and to examine the ecological and conservation implications for the species. This is the first radio-tracking study of wood mice inhabiting the cereal ecosystem.
Over three summers, 47 wood mice were radio-tracked in fields of winter wheat and 15,346 radio-fixes were collected.
Wood mouse social organisation may be summarised as female defence polygyny. Female mice defended intra-sexual territories (mean area = 2,547 m²), the size of which appeared to be determined by the dispersion of food resources. Male wood mice occupied, but did not defend, large home-ranges (mean area = 12,223 m²) which overlapped the territories of several females. The activity patterns of mice reflected the foregoing inter-sexual differences: males moved significantly faster and further than females. Mean values for the distance moved each night were 1,093 m for males and 402 m for females; wood mice were capable of travelling up to 2.4 km in a single night.Activity was essentially nocturnal, although over the short summer nights wood mice were routinely active for up to 2 hours both before dusk and after dawn. There was a peak in activity shortly after dusk with a second, much lesser, peak just before dawn.Wood mice often used more than one (range = 1-6) underground burrow within their home-range as daytime refuges, although females showed greater fidelity to a single burrow than males. This was probably because the burrow also functioned as a nest-site and nursery for females. Males were observed to share burrows whilst females were not. The burrows were positioned at random with respect to the configuration and habitat composition of the home-range. Experimental reduction of pesticide application onto the cereal crop produced small areas of high food availability in the field headlands which have been shown to be of conservation benefit to other species of farmland wildlife. The wood mice foraged in these blocks intensively, showing a statistically significant preference for such areas.The trauma associated with the autumnal harvesting of the cereal crop resulted in high mortality of the adult wood mouse population. This was mainly due to an increase in predation after harvest, which appeared to arise due to a combination of reduced cover for the mice and a concomitant change in the hunting strategy adopted by the predators.