Daily Activity Patterns Of Western Toads (Bufo boreas) On The Targhee National Forest, Idaho

Abstract

Populations of many amphibian species appear to be declining in locations all over the world, including the Pacific Northwest (Bartelt and Peterson 1994). As an example, the populations of Bufo boreas have undergone drastic declines throughout much of their range (Com and Fogelman 1984, Peterson et al. 1992, Carey 1993, and Blaustein et al. 1994). If we want to answer questions about amphibian decline and plan to conserve species such as Bufo boreas, we must first have knowledge of the natural history and normal behavior of healthy animals, preferably in their natural environments. With the use of radiotelemetry techniques I conducted a focal study and gathered information on the daily activity, behavior, requirements, and location during different times of the day of Bufo boreas. I found that the surface activity rate increased during the night, and increased moderately during the mid-day. Surface activity rate occurred over a broad range of temperatures and increased as relative humidity increased. Locomotion rate increased during the night as toads moved from a daily retreat site to water or warm substrate. Locomotion rate was low at temperatures above 16 °C, with most locomotion between 5 and 16°C. Locomotion rate increased as relative humidity increased. Feeding strike rate was highest during the mid-day and occurred over a broad range of temperatures and relative humidities. My study uncovered aspects of activity and behavior that were not previously known. This information provides the raw material from which further research questions and hypotheses can be formulated to determine the vulnerabilities of Bufo boreas.