400 University of California Publications in Zoology [Vol.12 



The fauna of the Trinity region seems to be best dealt with, by 

 considering its Boreal zonal elements, and its Sonoran (or Austral) 

 zonal elements, separately. Adjacent Boreal faunas are those of: 

 (1) the Sierra Nevada of east central California, (2) the Cascades 

 of Oregon, (3) the Humboldt Bay division of the Humid Coast 

 Belt. Adjacent Sonoran faunas are those of: (1) the Sacramento 

 Valley, (2) the Modoc region of northeastern California, (3) the 

 Humid Coast Belt. The following tabulations will serve to segre- 

 gate the pertinent facts appropriately: 



Table 1. Boreal species of the Trinity region which occur also on both 

 the Sierra Nevada and the Cascade Mountains, but not as regular members 

 of the humid coast fauna. 



MAMMALS 



Canis lestes (there are indications that a separate form exists in the 

 area towards the coast from Mount Shasta, of which the Trinity 

 region is a part). 



Martes caurina caurina (subspecific status in doubt; probably differ- 

 ing from the Cascade animal and most nearly identical with a 

 Sierran race). 



Martes pennanti pacifica (subject to same remark as above). 



Microtus mordax mordax. 



Eutamias amoenus amoenus. 



Eutamias senex. 



Callospermophilus chrysodcints trinitatis (very slightly different 

 from C. c. chrysodeirus of the Sierras and Cascades). 



BIRDS 



Dryobates villosus orius (intergradient towards the humid coast form 



Jiarrisi). 

 Xenopicus albolarvatus albolarvatus. 



Asyndesmus leuisi (possibly not to be considered Boreal). 

 Stellula calliope. 



Empidonax wrighti (possibly a straggler, merely). 

 Nucifraga Columbia ua. 

 Carpodacus cassini. 

 Melospiza lincolni lincolni. 

 Oreospiza chlorura. 

 Vermivora ruficapilla gutturalis. 

 Dendroica auduboni auduboni. 

 Dendroica nigrescens (not strictly Boreal). 

 Dendroica occidentalis. 

 Certhia familiaris zelotes. 

 Penthestes gambcli gambeli. 

 Myadestes toicnsendi. 

 Sialia currucoides. 



