534 abstracts: zoogeography 



continental life areas all but two occur in Wyoming; and their interre- 

 lationships are, as would be expected, greatly complicated. These five 

 zones with a few of their characteristic species are as follows: 



The Upper Austral Zone (represented here by its western arid sub- 

 division, the Upper Sonoran), which occupies most of the valleys and 

 lower plains, is the home of the broad-leaved cotton wood, juniper, 

 salt bush and yucca; of such mammals as Eutamias minimus pictus, 

 Citellus tridecemlineatus parvus, Lepus californicus melanotis, and of 

 such breeding birds as Zenaidura macroura marginella, Tyrannus 

 vociferans, Passerina amoena, and Icteria virens longicauda. 



The Transition Zone, which embraces the high plains, the basal 

 slopes of the mountains, and all the foot-hills except the highest, and 

 covers fully half the State, is characterized by yellow pine, narrow- 

 leaved Cottonwood, and sage brush; such mammals as Odocoileus vir- 

 ginianus macrourus, Sciurus hudsonicus dakotensis, Neotoma cinerea 

 cinerea, and Lepus townsendi campanius; and such breeding birds as 

 Centrocercus urophasianus , Cryptoglaux acadica acadica, Empidonax 

 wrightii, Cyanocephalus cyanocephalus, and Hylocichla fusescens sali- 

 cicola. 



The Canadian Zone, which covers the middle mountain slopes and the 

 highest foot-hill ranges, is the boreal forest belt of spruce, fir, lodge- 

 pole pine, and aspen ; and is furthermore delimited by such mammals as 

 Alces americanus shirasi, Glaucomys sahrinus bangsi, Phenacomys oro- 

 philus, Evotomys gapperi galei, and Lepus americanus americanus; 

 and such birds as Charitonetta arbeola, Nuttallornis borealis, Melospiza 

 lincolnii lincolnii, and Sitta canadensis. 



The Hudsonian Zone, which is a narrow belt covering the timber line 

 region, is marked chiefly by the white-barked pine, dwarfed spruce and 

 fir; together with such mammals as Ovis canadensis canadensis, Eu- 

 tamias oreocetes, and Ochotona uinta; and such birds as Nucifraga Colum- 

 biana and Pinicola enucleator montana. 



The Arctic- Alpine Zone, which occupies the mountain crests and the 

 portion of the peaks above timberline, is a treeless area, the vegetation 

 of which is limited to low bushes and other humble plants like Dryas 

 octopetala and Poa arctica, and is the home of such breeding birds as 

 Lagopus leucurus altipetens, Leucosticte australis, Leucosticte atrata, 

 and Anthus spinoletta rubescens. 



Under each of these zones detailed lists of mammals, breeding birds, 

 and plants are given, and a further list showing the distribution of all 

 the conspicuous trees and shrubs of Wyoming which are of importance 

 in delineating the life zones is also added. 



Harry C. Oberholser. 



