Status of Pacific Martens (Martes caurina) on the Olympic Peninsula, Washington

Abstract Pacific martens (Martes caurina) remain common in montane regions of the Pacific states, yet their distribution and status on the Olympic Peninsula, Washington, is uncertain. Between 1968–2008, six reliable marten detections exist; a dead juvenile female (2008) indicates martens were reproducing on the Peninsula within the last decade. To assess the status of martens, we describe carnivore surveys conducted from 1991–2008 (n = 223 stations). Additionally, we present results from three survey efforts we conducted from 2013–2016 (n = 747 stations). Although a suite of carnivore species was detected, surveys from 1991–2008 failed to detect either martens or fishers. Surveys from 2013–2016 detected reintroduced fishers, and resulted in two marten detections near Mt. Olympus, 4 km apart. A marten was photographed opportunistically near Mt. Cruiser in 2015, 44 km from Mt. Olympus. Altogether, nine reliable detections of Pacific martens were obtained between 1968 and 2016, including three since 2008. Evidence suggests martens are absent from the lower elevation regions they once occupied and occur at exceedingly low densities at higher elevations. To understand the trend in marten populations on the Peninsula and develop appropriate conservation strategies, additional broad- and fine-scale surveys using detection devices that enable the genetic identification of individuals will be needed.