THE ECOLOGY OF HOUSE MICE (MUS-DOMESTICUS) IN AND AROUND IRRIGATED SUMMER CROPS IN WESTERN NEW-SOUTH-WALES

A 28-month live-trapping survey was undertaken to investigate the ecol ogy and biology of house mice in an irrigated summer cropping system i n western New South Wales. Five broad habitat types were examined: ref uge habitat (e.g. roadside verges, fencelines), grazed dryland pasture , and the irrigated summer crops soybeans, sorghum/maize and cotton. M ouse abundance in most habitats peaked around March-April in each year , and then declined to relatively low levels by the end of spring. Mic e were always present in refugia but were often at very low numbers or absent from pasture and cotton. Very few mice were caught on paddocks used for summer crops during their fallow stage, but mice quickly app eared immediately following sowing. Of the summer crops, the maintenan ce of relatively high numbers of mice was greatest in the soybean crop s. Breeding occurred in several habitats throughout much of the year b ut was generally greatest in October-March. Grazed pasture and cotton had the least breeding females and refuge habitat the most. These resu lts are compared with other published studies, and their implications for management strategies are discussed.