INFLUENCE OF MINING ON BEHAVIOR OF BIGHORN SHEEP

Mining has been cited as detrimental to bighorn sheep (Ovis canadensis), but little research exists that has demonstrated those effects. We compared behavior of bighorn sheep while individuals were inside and outside of an active copper mine to determine if individual animals were altering their behavior relative to the active mine. We conducted this study in the Silver Bell Mountains, Arizona, from December 2003 to January 2005. We observed 3 radiocollared subadult males, 4 adult males, and 5 females, and recorded behavior throughout the daylight period. After accounting for differences by sex-age class (i.e., subadult male, adult male, female) and season (i.e., breeding, non-breeding), bighorn sheep fed less (6%) while inside the mine perimeter. Other behaviors (e.g., bedding, standing, alert, and interacting) were observed for similar amounts of time while within and outside the mine perimeter. Within sex-age classes, there were few differences in behavior. Subadult males fed less (mean difference = −18.6%, 95% C.I. = −43.1–6.0) and bedded more (mean difference = 14.3%, 95% C.I. = −40.9–69.4) while inside the mine. During the breeding season, adult males were alert less and interacted less (alert, mean difference = 4.1%, 95% C.I. = −1.63–9.9; interacting, mean difference = 3.1%, 95% C.I. = −5.7–11.9) while inside the mine. Females interacted more (mean difference = 0.37%; 95% C.I. = −0.01–0.8) while inside the mine area. Elements of modern mining activity (e.g., vehicular traffic, humans afoot near vehicles, sounds) might be predictable to bighorn sheep allowing them to habituate to those human activities.