Current knowledge of fisher (Pekania pennanti) breeding strategies and timing of mating is limited and comes primarily
from captive fishers. We used photographic data collected from 2010
through 2017 on a population of reintroduced fishers in northern
California to test several hypotheses about fisher reproduction,
breeding, and male-female interactions. We use logistic and linear regression to evaluate the timing and frequency of male visitation and reproduction at 262 reproductive dens used by 50 individual females. Of 46 documented copulations and 593 male visits, 100% and 95% occurred while females had kits in their natal dens. Seventy five percent of documented male visits occurred before 31 March and 95% of occurred before 18 April. Mating occurred during a short period (mean = 3.1 +/- 1.6 days) and all copulations were documented < 2 weeks following parturition. We documented fishers of both sexes breeding with multiple partners in the same year, demonstrating a polygynandrous mating system. We found no evidence for male directed infanticide, suggesting males were not motivated to kill kits by either hunger or competition. Our results add precision to the timing of the reproductive cycle and provide the first descriptions of male-female interactions for wild fishers.