| Successful reproduction is critical to maintain populations; for many species, habitat plays a key role in providing suitable locations for females to give birth and care for young. Concern for the long-term persistence of fisher (Pekania pennanti) in the Sierra Nevada has involved efforts to protect habitat to support reproduction, but until recently few reproductive dens had been found in this area. From summer 2008 through 2014, we used telemetry to follow 34 adult female fishers with radiocollars to 247 reproductive dens on the Sierra National Forest, California. Females used cavities in live trees and snags to shelter kits and selected California black oaks (Quercus kelloggii) as natal (50%) and maternal dens (53%) more than any other tree species. Diameter of den trees was generally large for natal (mean dbh of hardwoods = 77 cm ± 22, conifers = 114 cm ± 28) and maternal dens (mean dbh of hardwoods = 75 cm ± 19, conifers = 106 cm ± 25). Mean canopy cover was relatively dense at natal (74% ± 13) and maternal dens (73% ± 14). We present findings on other characteristics of den structures and habitat selection at several spatial scales, and implications for regional fisher conservation. |