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Sierra Nevada bighorn sheep are gregarious, with group size and composition depending on gender and season. Spatial segregation by gender occurs outside of the mating season. Bighorn sheep ewes generally remain with the same band in which they were born. Males older than 2 years of age remain apart from females and younger males for most of the year. During the late fall and winter, the groups come together and concentrate in suitable winter habitat. During this time, males compete for dominance with behaviors like horn clashes. Breeding takes place in late fall, generally November and December. Lambing occurs between late April and early July on safe, precipitous, rocky slopes; most lambs in the Sierra Nevada are born in May and June. Ewes and lambs often occupy steep terrain that provides a diversity of exposures and slopes for escape cover.