Use of artificial cavities by Humboldt marten

Abstract

ABSTRACTMany species of wildlife require cavities in trees as locations for refuge or reproduction. In forests where the availability of cavities has been reduced, artificial cavities may provide surrogate locations. Artificial cavities are typically created using boxes and artificial cavity research has traditionally focused primarily on birds. However, there are numerous cavity‐dependent species of mammals that are of regional and global conservation concern, such as the Humboldt marten (Martes caurina humboldtensis). Martens (Martes spp.) are small mustelids that often use cavities for daily resting and seasonal reproductive activities. During June 2013 to September 2015, we tested an artificial cavity design, modified from a design successfully used for European pine martens (M. martes), for the Humboldt marten in northwestern California, USA. We built and installed 16 artificial cavities (“marten” boxes) in marten‐occupied areas that have been managed for timber production and likely have reduced cavity availability. We monitored each box with a remote‐sensing camera for 2 years to evaluate visitation and use by martens and other cavity‐dependent species. Eleven mammal species visited ≥1 boxes and 4 species entered the box to use it. Martens had the greatest number of box‐use events, several martens used boxes for resting, and ≥1 female marten used a box for reproductive activities. Our results indicate that our boxes may provide artificial cavities for Humboldt martens in forests where natural cavities have been reduced due to timber harvest or severe wildfire. © 2018 The Wildlife Society.