Sexual differences in the ecology and habitat selection of western toads (Bufo boreas) in northeastern Oregon.

Abstract

Several species of toads (family Bufonidae), including the Western Toad (bufo boreas) have declined in the Western United States. Information on toad ecology and habitat use is essential to determine potential causes for population declines, as is the potential relationship between this information and disturbance events. Aspects of western toad survival, mortality, movements, habitat selection, and diet were investigated at five study areas in northeastern Oregon during September of 2002-2005. Of 100 radio-tagged toads monitored for one summer during these years, 32% survived until September, 29% were killed by predators, 10% died of other causes, and 29% were missing or had lost transmitters. At four study areas sampled in 2005, 24% of 37 males and 44% of 32 females sampled during the breeding season, and three dead male toads found after the breeding season tested positive for Batrachochytrium dendrobatidis. Females traveled significantly farther than males, and the maximum distances traveled by female and male toads were 6230 m and 3870 m, respectively. Toads with transmitters selected habitats: (1) with little or no canopy; (2) on south-facing slopes; (3) near water; and (4) with high densities of potential refugia (e.g., burrows, rocks, logs). Males were more closely associated with water than females. Twenty-six toads overwintered in rodent burrows (38%), under large rocks (27%), under logs or root wads (19%), and under banks adjacent to streams or a lake (15%). Diet consisted of 82% ants (Formicidae), 13% beetles (Coleoptera), and

Citation

Bull, Evelyn L. 2006. Sexual differences in the ecology and habitat selection of western toads (Bufo boreas) in northeastern Oregon. Herpetological Conservation and Biology. Vol. 1(1): 27-38