Ruffed Grouse occur only in the far northwestern portion of California, a relatively mountainous, remote, and sparsely populated region. Ruffed Grouse were described as more widespread and fairly common locally by Grinnell and Miller (1944) but as an uncommon breeder by Yocum (1978). Habitat use of this species in California is only known from anecdotal or descriptive studies.
The proposed project would generate a species distribution model (SDM) and conduct pilot field sampling and trend monitoring program design, covering the statewide distribution of Ruffed Grouse in California, in Del Norte, Humboldt, Mendocino, Siskiyou, Trinity, Tehama, and Shasta Counties. The SDM will utilize presence-only data from Breeding Bird Survey routes, museum specimens, and filtered expert reports with species distribution modeling to generate a predictive model of the habitat suitability of Ruffed Grouse throughout their range in northwestern California (Objective 1). We would then use a stratified random procedure in conjunction with the SDM to generate a prospective set of representative 200 survey sites on public lands in northwestern California (Objective 2).
The project will collect a pilot season of drumming survey data collection using one senior field technician and two student assistants, monitoring at least 150 of the selected sites using Ruffed Grouse drumming surveys and establishing drumming phenology throughout the region to economize future monitoring efforts (Objective 3). We would then use these data to evaluate site selection, sampling variance, and ultimately, provide a prospective design for a long-term trend analysis program for trend detection (i.e., determine the final sample and design needed to achieve a desired power for trend monitoring; Objective 4).