Avian Species Diversity and Habitat Use in Forests of the Sierra Nevada, California

DOCTORATE DISSERTATION: Patterns of species diversity in avian communities were examined in a successional sequence of post-burn conifer forest at mid-elevation in the Sierra Nevada in central California from 1969 to 1971. Habitats representative of the early (brush), middle (brush conifer) and late (forest) stages of secondary succession were studied intensively. I. In this study, avian communities in three representative seral stages of secondary forest succession were studied intensively for three years, 1969 through 1971, in the Sierra Nevada of California. Species diversity of birds relative to vegetational structure, insect productivity, habitat use and diet were examined as factors determining species diversity. This paper deals with the first two aspects. II. Increase in species numbers by addition to existing guilds is particularly interesting because the matrix of possible competitive interactions between the matrix of possible competitive interactions between species becomes progressively more complex. This study is an attempt to test these theories as they apply to the numbers of species of birds in two guilds of birds which occur in differently aged habitats of the guild on foraging substrates and foods, and how do they compare with regard to niche breadth and specialization? How do they differ between guilds?