Preliminary Data Used to Assess the Accuracy of Estimating Female White-Tailed Deer Diel Birthing-Season Home Ranges Using Only Daytime Locations

Because many white-tailed deer (Odocoileus virginianus) home-range and habitat-use studies rely only on daytime radio-tracking data, we were interested in whether diurnal data sufficiently represented diel home ranges. We analyzed home-range and core-use size and overlap of 8 adult-female Global-Positioning-System-collared deer during May and June 2001 and 2002 in the Superior National Forest, Minnesota, USA. We used two traditional means of analysis: minimum-convex polygons (MCP) and fixed kernels (95% FK, home range and 50% FK, core use) and two methods to partition day and night location data: (1) daytime = 0800-2000 h versus nighttime = 2000-0800 h and (2) sunup versus sundown. We found no statistical difference in size of home-range and core-use areas across day and night comparisons; however, approximately 30% of night-range areas on average were not accounted for using daytime locations, with even greater differences between core-use areas (on average approximately 50%). We conclude that diurnal data do not adequately describe diel yearling and adult-female-deer, home-range size and location during May and June, especially core-use estimation (50% FK). In analysing both yearling and adult-female-deer location data during a period that includes parturition we were studying a worst-case scenario. We suggest research to determine (1) if our findings hold under more-ideal circumstances (e.g., all adult deer, exclusive of the parturition period), (2) if our conclusions generalize under other conditions, and (3) if habitat-use conclusions are affected by the incomplete overlap between diurnal and diel data.