Population and movement characteristics of radio-collared striped skunks in North Dakota during an epizootic of rabies.

We observed a total of 102 striped skunks (Mephitis mephitis) from March to July of both 1991 and 1992 in Stutsman County, North Dakota (USA) during an experiment with food supplementation. Twenty-three apparently healthy skunks in 1991 and 56 in 1992 were equipped with radio-collars. In 1991, one of the 23 was tested and found to be rabid. In 1992, 50 of 56 were tested; 35 (70%) were rabid. Of skunks with ages estimated, 19 (66%) of 29 were first year animals in 1991 compared with nine (22%) of 41 first year animals in 1992. All 18 females captured in 1991 were pregnant or parous compared with 21 (60%) of 35 in 1992. The estimated survival rate of skunks was 0.85 during April to June 1991, but only 0.17 during April to July 1992. In 1992, the survival rate of first year skunks was 0.08, compared with 0.35 for older animals. Eleven (31%) of 36 skunks found dead of rabies or in late clinical stage were located below ground. We detected no differences in 1992 between healthy and rabid skunks in estimated mean (+/- SE) rate of travel (232 +/- 14 m/hr), distance traveled (2,047 +/- 141 m/night), or home range size (1.6 +/- 0.4 km2) during half-month periods from April through June. Among rabid skunks, mean rate of travel tended to decrease from 298 +/- 48 m/hr during the 14 days preceding the clinical period of rabies (pre-clinical) to 174 +/- 48 m/hr during the clinical period of rabies (14 days immediately before death). Similar decrease occurred in distance traveled in a night (2,318 +/- 281 m, pre-clinical; 1,497 +/- 281 m, clinical). Mean home range size of males (2.8 +/- 0.4) was greater than of females (1.2 +/- 0.4) during the pre-clinical period, but during the clinical period home range sizes of males (1.8 +/- 0.4) and females (1.8 +/- 0.4) were similar. Mean home range size of females did not differ between pre-clinical (1.2 +/- 0.4) and clinical (1.8 +/- 0.4) periods (P = 0.22). Deaths of skunks from rabies in 1992 tended to be more spatially clumped than expected had they been random, mostly due to deaths detected before 8 May. We detected no correlation between locations of animals found dead of rabies and dates of death.