1914] GrinneU: Mammals a)id Birds of the Cnlorado Valley 



Peromyscus maniculatus sonoriensis: Neotoma albigula venusta: min. 



min. Svlvilagus auduboni arizonae: max. 



Remarks upon the Quail-bnisli Assoeiation. — The local hunters at 

 Needles and other towns along the river apply the term quail-brush 

 to Atriplex lentiformis, a plant growing in dense clumps three to eight 

 feet in height along the outer margin of the flood-bottom. The belt 

 of this plant is so well marked and continuous, and the important 

 relations borne to certain animals are so evident, that tlie writer is 

 led to designate it separately by the name quail-brush association (see 

 pi. 6. fig. 6). 



Atriplex lentiformis often forms pure growths of a few yards to 

 many rods in width on ground at about the upper limit of the 

 average annual overflow. It was seen by us only in immediate prox- 

 imity to the flood-bottom, and hence was essentially a riparian element. 

 different from the other species of Atriplex inhabiting the region. 



The peculiar feature of the quail-brush was its compactly inter- 

 lacing network of branches, so den.se and resistent that a person 

 might throw his whole weight against a thicket onl.y to be hurled back 

 by the elastic rebound. The value of the plant to the animals affect- 

 ing it consisted pre-eminently in the protecting cover afforded. Quail 

 and cottontail rabbits when frightened took refuge in runways or 

 natural spaces beneath its tangled mass: and bush-inhabiting sparrows 

 of several species seemed to find ideal shelter in it. 



Although serving thus as a temporary shelter to animals regularly 

 foraging in other a.ssociations. the quail-brush a.ssociation also pro- 

 vided a safe breeding place for such birds as Pipilo aberti, Guiraca 

 and Melospiza. In places, clumps of quail-brush alternated with 

 mesquites, and here To.rostoma erissale found particularly congenial 

 ground. 



JIesquite Associ.vtiox 

 BIRDS 



Lophortyx gambeli: min.; resident Centurus uropygialis: min.; resident 

 Accipiter velox: min.; winter (only as a forager) 



Dryobates scalaris cactophOus: min.; Myiarehus cinerascens cinerascens: 



resident (onlj- as a forager ?) min.; transient 



Sphyrapicus varius nuchalis: max.; Myiochanes riehardsoni richardsoni: 



winter min.; transient 



