Date of this Version
Activity patterns in animals are influenced by a number of factors, including the animal's physiological adaptations, prey availability and distribution, and disturbances caused by predators and humans. We compared coyote (Canis latrans) activity patterns estimated using radio-tracking locations between 1983 and 1988 with those documented between 1996 and 1997 on the Pinon Canyon Maneuver Site, in southeastern Colorado. We tested the hypothesis that changes in the type of disturbance experienced by coyotes would result in changes in their activity patterns. Disturbance experienced by the coyote population studied during 1983-1988, included >50 years of intense exploitation (shooting and trapping by ranchers) and intensive removal efforts using aerial gunning. In contrast, coyotes tracked during 1996-1997 experienced some periodic disturbance from army maneuvers occurring in the area, but were not exposed to any direct form of persecution (e.g., shooting). From August 1983 to July 1988, 49 coyotes (26 males and 23 females) were tracked for >2400 h using radiotelemetry. From April 1996 to August 1997, 22 coyotes (12 males and 10 females) were tracked for >950 h. The average rate of diurnal movement of the coyotes in the 1996-1997 field study (Χ̅ = 0.97 km/h) was significantly higher than that of the coyotes in the 1983-1988 field study (Χ̅ = 0.68 km/h). This occurred despite no significant increase in the overall (24 h) rate of movement between the two field studies. Estimates of prey use by the coyotes in both field studies were obtained, to test an alternate hypothesis that prey switching might explain the changes in coyote movement patterns. However, there was no significant difference between the frequency of occurrence of diurnally versus nocturnally active mammalian prey species in the diets of coyotes in any season or overall between the 1983-1988 and 1996-1997 field studies. This study demonstrated that coyote activity patterns can be influenced by the type of disturbance experienced by the animal. A coyote population that had historically been exposed to human persecution shifted to higher levels of diurnal activity when exploitation ceased.