The current distribution and status of populations of the southwestern toad, Bufo microscaphus, are of considerable interest given the suspected decline in anuran amphibians in the western United States (Blaustein and Wake 1990, Sweet 1991). This bufonid, typically associated with riparian habitats in the desert Southwest, is largely absent from much of its former range in southern California (Sweet personal communication). In Arizona and Utah, B. microscaphus is known to hybridize with a closely related toad, B. woodhousii, and it appears that B. woodhousii has replaced B. microscaphus at a number of localities (Sullivan 1986). Given the interest in this species and the lack of information on populations in Arizona, I initiated a [...]
