DISTANCES AS INDEXES TO MOVEMENTS AND HOME-RANGE SIZE FROM TRAPPING RECORDS OF SMALL MAMMALS

Measurements of movements, such as the mean squared distance from the center of activity (r(2)), do not provide estimates of home-range size but are indices of use of space that can be compared among groups of mammals. We analyzed trapping data from Microtus ochrogaster and Sigmo don hispidus and found strong correlations among r(2) and several othe r measurements of distances moved and home-range size. The first princ ipal component of the correlation matrix retained from 77 to 91 % of t otal variation in movement among individual rodents. The P-values and coefficients of determination from analyses of variance among sex and age groups generally agreed for all indices of home-range size. The r( 2) provided an index of home-range size that was unbiased with regard to sample size, reflected tendency to localize movements, and could be pooled among individuals with small sample sizes.