Furbearer Activity Relative to Habitat in Pictured Rocks National Lakeshore

Abstract

Occurrence of furbearers, habitat use, and movements relative to weather were studied from winter trail counts and scent stations in northern Michigan in Pictured Rocks National Lakeshore, January 1989-August 1990. Winter trail counts indicated that the coyote (Canis latrans) was the most common furbearer. Coyotes averaged 0.54 trails/km of transect. Marten (Martes americana) trails were 37% less common than coyote trails. Trails of river otter (Lutra canadensis) were 82% less common than coyote trails; mink (Mustela vison), and long-tailed weasel (Mustela frenata) trails were 85% less common than coyote trails. Red fox (Vulpes vulpes) trails were 93% less common than coyote trails. All species averaged 0.12 trails/km of transect. Vegetation in Pictured Rocks National Lakeshore is dominated by northern hardwoods, which constitute about 40% of the total area. Combined with the mixed hardwoods/conifer type this component makes up> 72% of the total area. According to winter trail counts, more furbearer trails were observed than expected in hardwood, lowland, and dune habitats. Of the total furbearer trails observed, 41% occurred in northern hardwoods, 18% in lowland, 15% in conifer, 13% in edge, 7% in lake habitat, and 3% in dune. Of the total trails observed in 1990, 28% occurred~ 91 m from a habitat edge. Of the trails observed in edge, 65% occurred~ 0-23 m from the edge, perhaps because more prey occurred in the edge. Furbearer visits to scent stations were infrequent; therefore, I averaged visits by habitat and expressed them as a percentage of stations visited. Raccoons (Procyon lotor), the most common hibernal furbearer at scent stations, visited 7% of the stations. Striped skunks (Mephitis mephitis) visited 5.5%, and marten (Martes americana) 4.4% of the scent stations. Furbearers visited 14% more scent stations in fall than spring, perhaps because of annual recruitment. Of the total furbearer tracks in scent stations, 65% occurred in northern hardwood habitat, 15% in conifer habitat, 11% in edge habitat, and 6% in mixed hardwood/conifer habitat. According to scent stations, all habitats were used proportionately. But more furbearer tracks were observed than expected in conifer habitat. The best measure of habitat use by most furbearers in general was winter trail counts. These indicated that northern hardwoods, conifer, lowlands, dune, and edge were used proportionately, none was selected, and lake habitat was avoided. I found no evidence of occurrence of gray fox (Urocyon cinereoargenteus), badger (Taxidea taxus), lynx (Felis lynx), cougar (Pelis concolor), or wolverine (Gulo gulo). Aerial beaver (Castor canadensis) surveys revealed a mean of 0.21 colonies/km^2 and a mean ratio of inactive:active lodges of 1.1:1, indicating frequent recolonization, which might be due to poor habitat. Selection and avoidance of habitats by species of furbearer is presented.