COYOTE ACTIVITY LEVELS IN RELATION TO PRESENCE OF CALIFORNIA GULLS ATMONO-LAKE, CALIFORNIA

Islands which have historically supported breeding colonies of Califor nia gulls (Larus californicus) at Mono Lake, California have recently become peninsularized, allowing access to them by coyotes (Canis latra ns). Coyote ecology is important in Mono Lake Basin because invading c oyotes may cause gulls to abandon breeding colonies. We monitored coyo te activities by using movement-sensitive radio collars and hypothesiz ed that coyotes would shift their activity rates in response to presen ce or absence of California gull prey. Coyotes did change their activi ty rates between seasons, but they did not adjust their activity level s to take advantage of nesting gulls' nighttime vulnerability. We also analyzed the activity data to look for relationships between tight le ver and activity and between temperature and activity. Our results sug gest that prey abundance and light level may not be as important in in fluencing coyote activity levels as temperature.