Bird life has been studied in burned and unburned grassland and chaparral habitats of the San Gabriel Mountains since a major fire in November 1975. Since the fire, 85 species representing 26 families have been observed. The number of species breeding in unburned chaparral and in burned areas at 975 and 1280 m was essentially the same for three breeding seasons. Some chaparral species occurred in lower relative numbers on burned areas, some were more abundant, and others were not found at all. Birds specialized for taking insects on the wing were more abundant over burned chaparral, and seed and insect feeders were more abundant on burned areas. The number of species present in burned and unburned grassland habitats was lower than that in chaparral areas, and unburned grassland had the lowest number of species, in three seasons studied. Seasonal diversity patterns were similar in burned and unburned areas of both habitats, with diversity in grassland being lower than chaparral. Diversity in burned chaparral was greater than in unburned chaparral during breeding seasons. Though species number did not differ significantly between the two areas, numbers of individuals did, accounting for this difference in diversity indices. Chaparral fire may eliminate some species temporarily for post-fire seral stages, but most chaparral species can quickly reinvade burned areas. Increased seed and insect availability apparently permits burned habitats to support a greater number of individuals of chaparral species, and also attracts species not normally found in chaparral, resulting in increased diversity on recently burned areas.
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