Movements and Home-Ranges of Clethrionomys glareolus Schreber and Apodemus sylvaticus L. in North-East England

The movements and home ranges of the rodents Clethrionomys glareolus and Apodemus sylvaticus in Castle Eden Dene, County Durham (northeast England) were studied by capture-recapture methods from March 1963 to January 1965. Analysis of seasonal variation in movements revealed that both species range more widely in spring and summer than in winter, and males move further than females. Wandering and dispersal movements were found to be more common in Clethrionomys than was previously supposed. Home range sizes were estimated by four methods and were found to vary with species, sex, method of estimation used, and average number of captures per individual. The range sizes increased with class of animal in the order Clethrionomys female, Apodemus female, Clethrionomys male, and Apodemus male. In all classes the average trap-revealed range size increased continuously with increasing number of captures per individual, but showed signs of levelling off after ten captures. This increase occurred to a greater degree in males than in females and in Apodemus than in Clethrionomys. When the average number of captures per individual in the sample was the same, home range size estimates of increasing magnitude were obtained with methods ranked in the order: Minimum Area, Exclusive Boundary Strip, Manville's Method, and Inclusive Boundary Strip. Four patterns of movement were found in both species, viz. stable home range, change in home range, exploratory sallies, and dispersal. For animals caught seven or more times average range lengths were 67 m for Clethrionomys males, 49 m for Clethrionomys females, 76 m for Apodemus males, and 62 m for Apodemus females. Home ranges calculated by Manville's Method (which is considered to be the most realistic) for animals caught seven or more times, were 1970 m2 for Clethrionomys males, 1354 m2 for Clethrionomys females, 2250 m2 for Apodemus males, and 1817 m2 for Apodemus females.