Book Description

Primary prey for the protected subspecies California spotted owls (Strix occidentalis occidentalis) include dusky-footed woodrats (Neotoma fuscipes) (DFW) and Humboldt's flying squirrels (Glaucomys oregonensis) (HFSQ). The goal of my thesis is to describe fine-scale habitat use of DFW and HFSQ in industrially-managed timberlands in the Sierra Nevada Mountains of California. From 2018 to 2019, I live trapped and tagged 12 HFSQ and 31 DFW. From this sample, I fit five DFW and two HFSQ with radio transmitters (VHF) to assess fine-scale habitat use. I focused trapping on forest patches with mature and decadent trees, which are common habitat features associated with HFSQ and DFW occurrence. In Chapter One, I describe factors affecting trapping success of DFW and HFSQ. I used trapping success as an index of habitat use by prey, where higher trapping success equated to greater localized use by target species. I found a positive correlation between trap nights and capture probability for HFSQ. For DFW, I found capture probability positively correlated with trap nights and precipitation. In Chapter Two, I describe localized habitat features associated with HFSQ and DFW radio telemetry locations. I compared forest vegetation structure and composition in the immediate vicinity (within 5 m) of daytime locations used by HFSQ and DFW to more distal (>35m) vegetation conditions to determine if micro-forest structures corresponded to HFSQ and DFW use. I found species 0́3 level differences in percent ground and basal area where dusky-footed woodrats used areas with significantly more forest litter and shrub cover while Humboldt's flying squirrels used sites with larger diameter trees.