Understanding the Influence of Masting Hardwoods on Tree Squirrel Occupancies and Fisher Habitat Use in Northern California

$1,405 Awarded to Andria Townsend, Humboldt State University in 2017

Sciurids (tree squirrels) make up an important component of the fisher (Pekania pennanti) diet in California, with western grey (Sciurus griseus) and Douglas (Tamiasciurus douglasii) squirrels being the most commonly identified prey item in scat.  Masting trees such as members of the genus Quercus (oaks) and tanoak (Notholithocarpus densiflorus) produce the majority of acorns – an important component of the western grey and Douglas squirrel diet – in areas where tree squirrels and fishers co-occur.  Using the funds provided by a conservation grant from Sequoia Park Zoo, Andria Townsend, a graduate student at Humboldt State University, deployed 87 baited remote cameras to estimate tree squirrel occupancy rates in stands of differing tree species compositions.  She hypothesized that forest stands with mixed conifer/oak would support higher squirrel occupancy rates, and consequently would be selected disproportionately higher by fisher than other stands within their home range.  Results from her research will have direct conservation impacts by informing forest management practices that support healthy fisher populations by providing information on important tree species to leave in stands during timber harvest.