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 Mar ch to July of both 1991 and 1992 in Stutsman County, North Dakota (USA ) during an experiment wit food supplementation. Twenty-three apparent ly healthy skunks in 1991 and 56 in 1992 were equipped with radio-coll ars. In 1991, one of tile 23 was tested and found to be rabid. In 1992 , 50 of 56 were tested; 35 (70%) were rabid. Of skunks with ages estim ated, 19 (66%) of 29 were first year animals in 1991 compared with nin e (22%) of 41 first year animals in 1992. All 18 females captured in 1 991 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. Ele ven (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 (23 2 +/- 14 m/hr), distance traveled (2,047 +/- 141 m/night), or home ran ge size (1.6 +/- 0.4 km(2)) during half-month periods from April throu gh June. Among rabid skunks, mean rate of travel tended to decrease fr om 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 o f 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 femal es 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 ten ded to be more spatially clumped than expected had they been random, m ostly due to deaths detected before 8 May. We detected no correlation between locations of animals found dead of rabies and dates of death.