receiving low factor scores and those preferring trees or tall shrub- 

 dominated habitats receiving high values. Factor II seems related to habitat 

 homogeneity, canopy coverage, and topographic diveisity.-species preferring 

 complex, heavily dissected badlands habitats with steep slopes receive high 

 factor scores, and species preferring flat to rolling homogeneous grass- 

 lands receive low factor scores. As shown in the figure, habitat prefer- 

 ences for most species were remarkably similar between months and years. 

 Only seven species showed major differences (as indicated by Euclidean 

 distance ^^ 0.02 in the factor scores). The Western Meadowlark appeared 

 to select flatter, grassier habitats in 1978, as did the Marsh Hawk. The 

 Common Yellowthroat preferred habitats of higher foliage height diversity 

 in 1978, while the Clay-Colored Sparrow showed the opposite trend. Baird's 

 Sparrow (not encountered in 1977) showed a habitat shift toward flatter, 

 higher grasslands as the breeding season progressed. Horned Larks sel- 

 ected somewhat more diverse terrain in 1978. The most spectacular habitat 

 shift was shown by the Lark Bunting, which preferred flat, rolling grass- 

 land along the Circle and Dreyer Ranch routes in 1977 and sagebrush-badland 

 habitats along the Flowing Well route in 1978. 



SMALL MAMMAL COMMUNITY PARAMETERS 



Small mammal capture data for 1978 are summarized in Table 18. 

 As in 1977, small mammal population densities were highest in tall 

 coulee shrub habitats. The first long-tailed vole of the trapping 

 program was taken in this habitat in 1978. 



49 



