Northern Prairie Wildlife Research Center
Elise J. Gallerani Lawson1 and Arthur. R. Rodgers, Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, 955 Oliver Road, Thunder Bay, ON P7B 5E1 Canada
With the advancement of radio tracking techniques, there has been a dramatic increase in the quantity and quality of locational and movement data obtained for a variety of wildlife species. Automated tracking systems, in particular, produce enormous amounts of data that can be effectively handled only by some form of computer processing. The data collected help researchers determine daily movements, large scale movements, home ranges, and habitat use by individuals and populations. One of the many challenges is determining not only which home range estimators to use, but also which home range package will best fulfil study objectives. We used data (n = 483 locations) from a moose fitted with a test GPS collar to compare home range estimates determined by 5 commonly used software packages (CALHOME, HOME RANGE, RANGES IV, RANGES V, TRACKER). We found large differences in calculated home range sizes using Minimum Convex Polygon (MCP), Harmonic Mean (H), and Kernel (K) estimators at 3 levels of resolution (95%, 75%, and 50% of locations). For example, using 95% of the locations, estimates ranged from 39.96 to 62.26 km2 in MCP analyses, 31.60 to 90.98 km2 in HM analyses, and 14.45 to 39.95 km2 in K analyses. Comparing home ranges of animals among different research studies can be misleading unless researchers report the software package used, which home range estimators have been calculated, user-selected options for calculating each estimator, and the input values of required parameters. Indeed, changing home range analysis software during the course of a research project could invalidate comparisons within a single study.
1Present address: P.O. Box 891, Franconia, NH 03580 USA