DIFFERENCES IN HOME-RANGE SIZE COMPUTED IN COMMONLY USED SOFTWARE PROGRAMS

With the advancement of radiotracking techniques, there has been a dra matic increase in the quantity and quality of locational and movement data obtained for a variety of wildlife species. Automated tracking sy stems, in particular, produce enormous amounts of data. These data hel p researchers determine movements, home ranges, and habitat use by ind ividuals and populations. One of many challenges is determining not on ly which home-range estimators to use, but also which home-range progr am will best fulfil study objectives. We used data from a moose (Alces alces) fitted with a test Global Positioning System (GPS) collar to c ompare home-range sizes estimated by 5 commonly used software packages (CALHOME, HOME RANGE, RANGES IV, RANGES V, TRACKER). We found large d ifferences in calculated home-range sizes using minimum convex polygon , harmonic mean, and kernel estimators at 3 levels of resolution (95%, 75%, and 50% of locations). Comparing home ranges among different res earch studies can be misleading unless researchers report choices for software program, home-range estimators, user-selected options, and in put values of required parameters.