Detection of Endangered American Martens (Martes americana) in Apostle Islands National Lakeshore, Wisconsin

American martens (Martes americana) warrant concern in Wisconsin, U.S.A., for multiple reasons, including being the state's only endangered mammal and a clan animal of the Ojibwe tribes. American martens were once present throughout much of the state but were extirpated in the early 20th century through habitat loss and unregulated trapping. In the 1950s two reintroductions of martens to Stockton Island of the Apostle Islands archipelago were considered failures, with the last confirmed sighting in the archipelago in 1969. In the decades since the Stockton Island reintroduction efforts, anecdotal reports of martens have surfaced throughout the archipelago. In 2014-2016 we deployed 91 camera traps on 13 of the 21 Apostle Islands to survey the archipelago's extant carnivore species. We detected American martens at 28 of 87 functioning camera trap sites on 5 of 13 monitored islands and documented the existence of American martens in APIS in Wisconsin for the first time in over 50 y. We suggest continued research to evaluate the status of the APIS population and its potential origins to guide future conservation efforts.