328 University of California Publications in Zoology [VOL. 16 



those of the timber and brush from those of the stream shore. The 

 Yakima Valley belongs in the Columbia Basin sagebrush faunal area 

 and the environmental conditions of the sagebrush in that valley seem 

 to be very similar to those of the sagebrush in western Walla Walla 

 County. Of the species of birds stated to be characteristic of the sage- 

 brush of the Yakima Valley all except five, Sayornis say us, Otocoris 

 alpestris merrilli, Pooecetes gramineus confinus, Spizella breiveri, and 

 Oreoscoptes montanus, have been reported from the sagebrush of 

 western Walla Walla County. 



The roadside association recognized by Jackson (1914, pp. 23, 24) 

 in the conifer forests of Wisconsin belongs to a habitat at the edge of 

 a clearing in a heavy forest and seems to have many features in com- 

 mon with the forest-margin communities recognized in other regions. 

 Such an association might be recognizable in the Blue Mountains, but 

 roads are few in that area and it is impossible to define such an asso- 

 ciation without more data than is at present at hand. 



Animal habitats are sometimes divided into strata. Shelf ord (1913, 

 p. 165) recognizes five strata in some terrestial habitats, extending 

 from the subterranean stratum to the tree stratum. No attempt has 

 been made to divide the habitats of southeastern Washington into 

 strata, although various strata could undoubtedly be distinguished. 



Much has been made of the succession of animal species due to the 

 change in habitats induced or correlated with plant succession ( Adams, 

 1908). In southeastern Washington many of the associations and 

 habitats seem to have reached an equilibrium and succession is not 

 very prominent. In the sagebrush and prairie areas the rocky-slope 

 habitat tends to change to the sagebrush or bunchgrass habitat. Modi- 

 fications which occur by the shiftings of the stream channels produce 

 changes in the riparian associations. Floods sometimes wash out part 

 of the willow habitat and even at times part of the bunchgrass or sage- 

 brush habitat. Also, the willow habitat tends to invade the river beds. 

 At every shifting of the stream channel there are changes in the 

 extent and position of the water-margin habitat. In the Blue Moun- 

 tains the conditions are probably less stable and changes in habitats 

 are probably in more active progress. Weaver (1914) has suggested 

 that in Whitman County, Washington, and in the adjacent parts of 

 Idaho the succession is the following direction: (1) bunchgrass; (2) 

 yellow pine; (3) Douglas spruce and western larch; (4) cedar. Cedar 

 does not occur on the Blue Mountains as a distinct habitat, but its 

 place is probably taken by the alpine fir. 



