J. FURBEARERS 



1) Introduction 



The 52.5 miles of riverine habitat, 48.8 miles of tributary 

 streams, several bodies of standing water, riparian habitats, and 

 mosaics of forest and shrubland habitats inundated by Lake Koocan- 

 usa supported populations of many species of furbearers. Beaver, 

 muskrat, mink, river otter, pine marten, lynx and bobcat were the 

 species considered to be the primary furbearers within the area of 

 concern. Site-specific data descriptive of the occurrence and habi- 

 tat preferences of preproject furbearer populations were unavail- 

 able. Research reports specific to furbearer populations in the 

 region (Key 1979, Hornocker and Hash 1981, Zackheim 1982, Melquist 

 and Hornocker 1983, Wright et al. 1983) did provide descriptions of 

 key habitat requirements and seasonal distributions. As a group, 

 furbearers are currently ranked ninth in the management prioritiza- 

 ticai. 



2) Seasonal Habitat Preferences 



Beaver. Beaver occur in lakes, rivers, and marshes throughout 

 Montana (Wright et al. 1983). Atwater (1939) noted optimal habi- 

 tats for beaver in the South Fork of the Flathead River valley were 

 those areas where willows or populars were available along perma- 

 nent water courses; these were generally the larger tributaries. 

 It was assumed beavers utilized the Kootenai and Tobacco rivers, 

 larger tributaries, and backwater and slough areas within the area 

 of concern. 



River Otter. River otters probably utilized the majority of 

 the aquatic habitats within the area of concern. Zackheim (1982) 

 defined high quality river otter habitat in southwestern Montana as 

 streams with undercut banks and dense riparian vegetation. Also, 

 the presence of side channels and sloughs improves habitat quality. 

 Melquist and Hornocker (1983) found otters in west central Idaho 

 preferred valley habitats to mountain habitats, and streams 

 (rivers) to lakes, reservoirs or ponds. Mudflats, marshes, and 

 backwater sloughs were important to family groups during summer 

 (Melquist and Hornocker 1983). Fish are the main food item for the 

 river otter (Greer 1955a, 1955b, Zackheim 1982, Melquist and 

 Hornocker 1983). Marshes and sloughs provide a supply of slower 

 fishes and prey items utilized by juvenile otters (Zackheim 1982). 



Hink. Mink are highly reliant on aquatic and riparian 

 habitats (Key 1979, Melquist et al. 1981, Wright et al. 1983). 

 They are common carnivores along stream courses where they forage 

 in ri^)arian vegetation, overhanging banks, and log jams. 



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