Sample abundances were significantly and negatively correlated with cultivated 

 land (p<.001) and trees and tall shrubs (p<.01). The species arrives in the 

 study area in early April, and reaches peak sample abundances in June, July, 

 and August. Sample abundances drop quickly in late August and early September, 

 and most birds are gone by October. 



Loggerhead Shrike . The loggerhead shrike is a fairly common summer resi- 

 dent, preferring dense clumps of silver buffaloberry, especially at the heads of 

 coulees, as nesting habitat. Birds arrive in the study area in early April and 

 nesting reaches a peak in June and early July (figure 15). Sample abundances, 

 however, peaked in mid-July as noisy flocks of newly-fledged young appeared. 

 Of eight nests located during the study, six were located in silver buffalo- 

 berry and two in cottonwoods (table 10). Most birds are gone by September. 

 This species is replaced by its congener, the northern shrike, during the per- 

 iod from October through February (table 7). The Dreyer Ranch and Missouri 

 River routes showed highest sample abundances, corresponding to high repre- 

 sentation of tall shrubs (table 5). 



House Sparrow . Sample abundances of house sparrows were closely related 

 to the presence of buildings and farmsteads in the sample radius (figure 16, 

 table 5), and were thus greatest on the Circle and Missouri River routes year- 

 long. Lowest sample abundances were recorded during the period from December 

 through February. 



Western Meadowlark . The western meadowlark, the Montana state bird, was 

 one of the most abundant and widespread of all breeding bird species throughout 

 the study area. Although none were encountered on March runs of the roadside 

 routes, large flocks had arrived by the end of March, and peak sample abundances 

 were attained in April with the arrival of migrant flocks and the onset of ter- 

 ritory establishment (figure 17). Sample abundances showed a general decline 

 throughout the summer. A minor peak in September coincided with the fall move- 

 ment, and a fall increase in singing activity. Most birds were gone by mid- 

 October. It is interesting that monthly sample abundances, while consistently 

 somewhat lower for the Circle route and higner for the Prairie Elk route, were 

 very similar for all routes and followed the same pattern of summer-long decline. 

 This confirms the general observation that the species is very widespread, wery 

 eurytopic, and very common in grassland habitats throughout the study area. 

 Surprisingly, sample abundances of this grassland bird were not significantly 

 correlated with grassland, but were significantly and positively correlated with 

 silver sagebrush and saltgrass (p<.001). 



Red-winged Blackbird . Figure 18 shows sample abundance curves for the red- 

 winged blackbird. Peak sample abundances occurred during the nesting months from 

 April through June, and were greatest along the Missouri River route, which tra- 

 versed extensive cattail marshes in the Missouri River floodplain. Curves for 

 this route shows a unique pattern, in that autumn concentrations of migratory 

 flocks and winter residents occurred only in the extensive cattail habitats found 

 along this route. Most birds are gone from the upland habitats of the study area 

 by August. Sample abundances were significantly and positively correlated with 

 marshes, alfalfa, and trees and tall shrubs (p<.001), and were significantly and 

 negatively correlated with time and grassland (p<.001). 



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