-31- 



wlthout singing males were observed on the strip. Species with the highest 

 densities were western meadowlarks (50.0 pairs/100 ha), killdeer (14.3 pairs/ 

 100 ha) and eastern kingbirds (9.3 pairs/100 ha). 



A possible explanation as to why this type was least affected both in density 

 and diversity by the effects of the drought was that a majority of the nongame 

 birds found here were associated with the scattered cottonwoods which occurred 

 there (e.g. common flicker, red-headed woodpecker, kingbirds, house wrens, etc.). 

 In addition, the drainages received what little water was available from 

 snow melt and some new growth occurred. Also, constant grazing pressure 

 on this type could have the effect of lowering the values observed below what 

 would have occurred had the area remained ungrazed. Destruction of the cotton- 

 woods found in this type would have a very adverse affect on both densities and 

 diversities of nongame birds. 



Limber and Ponderosa Pine Subtypes 



Although no survey transects were conducted in these subtypes, time was spent 

 searching the areas to locate nongame bird species. Species unique to these 

 subtypes were the least flycatcher, pinon jay, red-breasted nuthatch, Swainson's 

 thrush, Philadelphia vireo, American redstart, western tanager, red crossbill, 

 and dark-eyed juncos. In addition, certain other species were found in their 

 greatest abundance in these timbered types (e.g. yellow-rumped warblers, chipping 

 sparrows and mountain bluebirds). Destruction of the timbered types on the 

 study area would result in elimination of species unique to these types and 

 drastic reductions in the numbers of those species found in greatest abundance 

 here. 



WINTERING BIRD SURVEY 



Results of the wintering bird surveys are presented in Table 4. These surveys 

 were conducted in January and February to avoid including late fall stragglers 

 and early spring migrants. Conditions were mild and open during the winter of 

 1979-80 and this probably increased the number of species observed over that 

 which occur in a severe winter. Data from only one winter make such conjectures 

 open to question. General observations, however, indicate a lack of birds 

 wintering on the area. Species of "special interest or concern" known to 

 winter on the area were the golden eagle and prairie falcon (wintering by bald 

 eagles, an endangered species, is covered in that section of the report). 



MAMMALS OF THE STUDY AREA 



A list of mammal species occurring on the study area, the vegetation type in 

 which they were most frequently observed, relative abundance and classification 

 is presented in Table 5. In addition, a discussion of individual species is 

 presented below. 



Merriam's Shrew (Sorex merriami) - Only one specimen of this species was captured 

 on the study area; therefore, it was listed as rare. Although this specimen 

 was captured in the creek vegetation type it generally inhabits arid sagebrush 

 desert, sagebrush-grass semi-desert, and occasionally dry grassland habitats 

 (Hoffmann and Pattie 1968). A possible explanation for the capture in the creek 



