pine forests, and red fir forests. In the Sierra Nevada, the western toad occurs in mid-elevation pine forests (including Jeffrey pine (Pinus jeffreyi) at higher elevations and ponderosa pine (Pinus ponderosa) at lower elevations), California black oak woodlands (Quercus kelloggii), giant sequoia groves (Sequoiadendron giganteum), montane fir forest (which includes white fir (Abies concolor), red fir (Abies magnifica], and western white pine (Pinus monticola)), and redwood forest (Sequoia sempervirens). It is also found in riparian areas within sagebrush-pinyon communities (Artemisia spp.-Pinus spp.), oak-pine woodland and savanna (including coast live oak (Quercus agrifolia), interior live oak (Quercus wislizenii), and canyon live oak (Quercus chrysolepis)), and California coastal forest and scrub. Western toads have been collected from sedge meadows near a pond occurring in a creosotebush (Larrea tridentata) community, and from aspen (Populus spp.)-willow groves within big sagebrush (Artemisia tridentata)-grassland. Life cycle Western toads are active from January to October, depending on latitude and elevation, and hibernate over the winter. Boreal toads in one Colorado population used natural chambers near a small stream bed. The high water table, constantly flowing stream, and deep winter snow served to maintain the air temperature within the hibernaculum at a point slightly above freezing. Emergence from hibernation followed a few days of warm temperatures that freed the entrance and increased temperatures within the chamber to about . At low elevations western toads are active at night; at high elevations and in the northern parts of their range they are diurnal. Body temperature of western toads is closely correlated with the substrate temperature. Basking and conduction from the substrate are primary means of increasing body temperature and cooling is achieved by evaporative cooling and conduction of heat to a cooler medium. Diurnal and nocturnal activity are often related to seasonal changes in temperature; most western toads are diurnal during the spring and fall but are nocturnal during the warmer summer months. In central Oregon, the minimum breeding age for male western toads is three years, and probably four or five years for females. California toads are reported as sexually mature at 2 years of age. Male western toads breed every year; females breed at less regular intervals, depending on individual condition and previous years' breeding effort. Sex ratios differ according to habitat type; males are more numerous in wet areas and females are more numerous in dry habitats. Eggs are laid in open water from February to