308 I' niversity of California Publications in Zoology [VOL. 16 



(Lupinus). Common sagebrush (Artemisia tridentata) and rabbit 

 brush (Ckrysotkamniu viscidiflorus and Chrysothamnus nauseosus 

 graveolens) occur sometimes in the bottoms of the drier ravines and 

 on exposed hillsides. In damp situations, in the bottoms of ravines 

 or on north hillsides, the rye grass (Elymus condensatus) forms large 

 clumps. Where the land has been much pastured the yarrow (Achil- 

 lea mille folium lanulosa) grows abundantly. There are also a number 

 of kinds of mustards and many other less important plants. In damp 

 places on the north hillsides a few woody shrubs may be found and 

 these are more numerous the more closely the mountains are ap- 

 proached. The more important of these are the rose (Rosa) and 

 service-berry (Amelanchier ftorida}. 



Near Prescott almost all of the bunchgrass hills have been plowed 

 and are planted to wheat and barley. On alternate years the land is 

 allowed to lie fallow. The bunchgrass which remains unplowed has 

 been heavily pastured, so that the grass has been partially killed out 

 and yarrow, lupine, and other weeds have greatly increased. 



The bunchgrass association includes a considerable number of 

 plains-loving species. 



Traps set in bunchgrass habitat in the hills two miles southeast 

 of Prescott produced, for a total of 148 "trap-nights," on June 27, 

 July 1, and July 7, 1914, five Perognathus lordi lordi. One of these 

 trap lines, of 33 traps, produced on the second day 's trapping, July 8, 

 one Peromyscus maniculatus gambelii. 



ROCKY-SLOPE HABITAT AND ASSOCIATION (PRAIRIE AREA) 



Major : 



Crotalus oregonus. Salpinctes obsoletus obsoletus 



summer. 



Minor: 



Pituophis catenifer catenifer. Tyrannus verticalis summer. 



Zenaidura macroura marginella Petrochelidon lunifrons lunifrons 



resident. summer. 



Buteo borealis calurus resident. Peromyscus maniculatus gambelii. 



Falco sparverius sparverius Sylvilagus nuttallii nuttallii. 



resident. 



There is usually very little sagebrush growing among the rocks in 

 the rocky-slope habitat of the prairie area. The wheat bunchgrass 

 (Agropyron spicatum) grows abundantly among the rocks wherever 

 soil is present. Along Snake River a few shrubs grow among the 



