| Collecting demographic data is time-consuming and expensive but allows monitoring of population trends. Further, locating reproductive structures (e.g., nests, dens) can be difficult, especially for species that use cryptic locations such as tree cavities. Surrogate cavity structures, or nest boxes, have commonly been used for conservation and monitoring of birds, but have rarely been tested on cavity-using mammals. The Humboldt marten (Martes caurina humboldtensis) is a cavity-obligate mustelid that has previously been proposed for federal endangered species listing. However, little information exists on Humboldt marten demographics; our objective was to assess the effectiveness of boxes as a population monitoring method. We designed marten-specific boxes and installed them in trees in cavity-poor coastal dune forests in Oregon. We monitored boxes (n = 19) with a remote camera for 4-12 months, over a single reproductive season. Martens used 9 boxes (64%) with at least 1 box used by a female marten and 1 kit. Three boxes had large numbers of scats (n = 7-45), inferring increased use. Boxes were also used by marten prey species such as squirrels. Our box design appears to provide suitable surrogate cavity structures, demographic and reproductive data, and scat to infer diet for an elusive forest carnivore. |