Resource partitioning by an avian guild in an oak woodland
Graduation Date
1988
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, 1988
Committee Chair Name
Barry R. Noon
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Birds--Behavior, Birds--Feeding and feeds, Bird populations, Humboldt State University -- Theses -- Wildlife Management
Abstract
Bird community structure was described in an oak woodland near Hopland, Mendocino County, California, between March 1986 and June 1987. The bird community was censused, the vegetative community was measured, and the foraging behavior of 20 insectivorous and/or granivorous bird species was observed on 23 5 ha study plots. Resource partitioning between bird species in the foliage-foraging guild was investigated. Seventy-three bird species were detected during censuses. Thirty-three species were insectivorous and confirmed breeders. Cavity nesters comprised a large proportion of the breeding bird community in terms of species (24.5 percent) and individuals (58.1 percent). Deciduous oak trees dominated most study plots, and blue oak was the most abundant deciduous oak. Floristics, structure, and elevation varied among study plots. The 800 m elevation gradient that existed among study plots was partially responsible for the variance in vegetative characteristics among plots. Three guilds (bark-, ground-, and foliage-foragers) were delineated based on frequency of use of substrates where foraging attempts were directed. The foliage-foraging guild consisted of 10 species. These 10 species were widespread, with an average of 90 percent frequency of occurrence across study plots. Year-round residents (three species) appeared to be more abundant than summer residents (seven species). Resource partitioning between bird species in the foliage-foraging guild occurred on both spatial and behavioral "axes". Spatial overlap was measured by habitat association, plant species use, and location on the plant. Behavioral overlap was measured by substrates and maneuvers used to obtain prey, search movements, and prey type. Spatial and behavioral overlap was extensive among species, but the abundance of each species and the frequency of use of resources and behaviors varied between species. All species differed significantly on one or more resource axes. The influence of residency, body size, and nest type on resource use is discussed.
Recommended Citation
Manley, Patricia N., "Resource partitioning by an avian guild in an oak woodland" (1988). Cal Poly Humboldt theses and projects. 1825.
https://digitalcommons.humboldt.edu/etd/1825
https://scholarworks.calstate.edu/concern/theses/vm40xv10k