The Winter Distribution of the North American River Otter in Acadia National Park, Mount Desert Island, Maine

Gerber, Rebecca

From the introduction: "The purpose of the study was to determine the habitat variables needed to discriminate between those watersheds used by otter in winter and those not used.....The current winter distribution of otters was determined by surveying 12 watersheds on the eastern side of Mount Desert Island between December 2009 and March 2010. Due to limited snow conditions, only 10 out of the original 12 watersheds were used in the analysis of this stud. For these 10 watersheds, a total of 28 sign surveys were conducted, in which 34 points of otter activity where found. Otters were documented by 5 different types of otter sign tracks, slides, latrines, dens, and holes in the ice. Watersheds were classified as used by otter if sign was found in a minimum of one survey and classified as unused if no otter sign was found in a minimum of two surveys. Otters were found to be present in 6 watersheds, and absent in 4. All 6 used watersheds were located in the northern part of the island, while the unused watersheds were located in the southern part of the island. The discrimination between used and unused watershed was attributed to three major habitat variables deepwater habitat (ponds deep enough to remain partially unfrozen during the winter), prey availability, and beaver activity. This study suggests that one variable alone cannot be used to accurately describe otter habitat. In order to do so, a combination of many variables must be used. This study will be provided to the park in order to assist with future studies and to help maintain populations of the North American River Otter in Acadia National Park, Mount Desert Island, Maine" /STUDY LOCATIONS:/ /MOUNT DESERT ISLAND/Northeast Creek/Breakneck Brook/Witchhole Pond/Duck Brook/Breakneck Ponds/Halfmoon Pond/The Tarn/Bear Brook/The Bowl/Schooner Brook/Hunters Brook/Stanley Brook/Little Harbor Brook/ GIS-CATEGORY 2 General map of study site locations provided;