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Grassl and - A total effort of 1,179 trap nights resulted in the capture of 19 

 small mammals in this type. Of these, eight were deer mice {Pevomysous maniaulatus) , 

 five prairie voles (Miarotus ockr'ogaster) , five Wyoming pocket mice (Perognathus 

 fasoiatus) and one western harvest mouse (Reithrodontomys megatotis) . Total 

 captures per 100 trap nights, 1.61, was low in this type, although diversity was 

 high with four species. 



Sage-Grassland - A total effort of 1,338 trap nights resulted in the capture 

 of 17 small mammals in this type. Of these, nine were Wyoming pocket mice, 

 seven deer mice, and one western harvest mouse. Captures per 100 trap nights 

 (1.27) were the lowest of all types sampled, but diversity was moderate with 

 three species. The Wyoming pocket mouse was dominant in this type while in all 

 of the other types sampled, the deer mouse was the most abundant species. 



Badlands - A total effort of 1,173 trap nights resulted in the capture of 144 

 small mammals in this type. All specimens captured were deer mice, resulting 

 in the lowest diversity of all types sampled; however, captures per 100 trap 

 nights (12.28) were the highest recorded for any of the vegetation types sampled. 



Cree k - A total effort of 1,093 trap nights resulted in the capture of 61 small 

 mammals in this type. Of these, there were 47 deer mice, nine prairie voles, 

 four Wyoming pocket mice and one Merrian's shrew {Sorex merriami) . In addition, 

 the fall sampling effort resulted in the capture of one western harvest mouse 

 bringing the number of species found in this type to five and making it the 

 most diverse of all the types sampled. Captures per 100 trap nights (5.58) 

 in this type were second only to that of the badlands type (12.28). Of the five 

 species captured in this type only the Merriam's shrew is listed as being a 

 species of "special interest or concern" for Montana. This specimen was the 

 first of its species captured in a creek vegetation type (Flath, pers. comm.). 

 The number of prairie voles captured in this type is of interest in that they 

 were fairly common and voles were shown to be an important item in the diets of 

 predatory birds and mammals (Riechel 1976, Flath 1979c). 



Ponderosa Pine Badlands Subtype - A total effort of 482 trap nights resulted in 

 the capture of 26 small mammals. Of these, 25 were deer mice and one was a least 

 chipmunk {Eutamias minimus). Captures per 100 trap nights (5.39) were high, 

 though diversity with only two species was low. The small mammal species 

 composition was similar to that found in the badlands type but densities were 

 lower. 



Limber Pine Badlands Subtype - Five hundred and eighty-three trap nights in this 

 type resulted in the capture of 24 small mammals. Of these, 21 were deer mice 

 and three were prairie voles. Captures per 100 trap nights were moderate (4.12) 

 although the number of species (2) was low. The presence of prairie voles in 

 this type can probably be accounted for by its proximity to the grassland type 

 and the grassy habitats that occur between the stands of pine. 



Grassland Coule e - These areas were sampled because it was felt that the unique 

 vegetation found in grassland coulees might support species of small mammals 

 not found in other types. The presence of snowberry (Symphoricarpos spp.), 

 rose (Rosa spp.), creeping juniper (Juniperms horizontalis) and skunkbrush 

 sumac (Rhus trilohata) provided a unique habitat situation. A total effort of 



