Press.</ref> and later authors, including Sawyer et al. This dense, shrub-dominated community of the California chaparral and woodlands is more highly developed on the north-facing slopes than on the drier, hotter south-facing slopes. Among the shrub species that characterize this community, prominent in the Verdugos are laurel sumac (Malosma laurina), toyon (Heteromeles arbutifolia), poison oak (Toxicodendron diversilobum), chamise (Adenostoma fasciculatum) and two species of California-lilac (Ceanothus crassifolius and Ceanothus oliganthus). Native trees are restricted to protected canyons, especially on the shadier north slope of the range, where soil moisture levels are higher. Coast live oak (Quercus agrifolia), California bay laurel (Umbellularia californica), California sycamore (Platanus racemosa), California walnut (Juglans californica), and several species of willow (Salix spp.) are the most common native trees. Non-native trees, particularly pines (Pinus spp.), cypress (Cupressus spp.), locust (Robinia pseudoacacia), and Australian eucalyptus (Eucalyptus spp.) have been planted locally along the fire roads and, most notably, in the Fire Warden's Grove, established in the wake of a wildfire in 1927. Except for a tenuous link to the large wild area in the San Gabriel Mountains through Big Tujunga Wash at their northwestern end, the Verdugo Mountains are an urban wildlife island completely surrounded by development. Among the large mammals, coyote (Canis latrans) and mule deer (Odocoileus hemionus) are the most common; mountain lions (Puma concolor) and black bears (Ursus americanus) have occasionally been reported. The many rodent species support a population of western rattlesnakes (Crotalus viridis). Of the numerous bird species present, the most characteristic of the chaparral here, and throughout California, is the small, seldom seen but often heard wrentit (Chamaea fasciata). With its call of three or four chirps followed by an accelerating trill, often likened to the sound of a dropped ping-pong ball, the wrentit provides the most characteristic sound of the chaparral. The Verdugo Mountains have warm, dry summers and cool wet winters. Snow infrequently falls along the crest during the coldest winter storms, but melts rapidly. Annual average precipitation increases with elevation (due to the orographic lift effect), from 17-21 inches at the base to about 24–28 inches at the crest. Annual rainfall totals are highly variable from year to year, with the higher totals usually in El Nino years. Most of the rain falls between November and March during periodic frontal passages. History The mountains were part of the indigenous Tongva people's homelands for over 7,000 years, with villages