34 



.Parus hudsonicus columbianus. Columbian Chicka- 

 dee. 



Regulus satrapa olivaceus. Western Golden-crowned 

 Kinglet. 



Hylocichla alicise. Gray-cheeked Thrush. 



Hylocichla ustulata almae. Alma's Thrush. 



Ixoreus naevius. Varied Thrush. 



MAMMALS. 



Contrary to expectations, small mammals were very scarce 

 on the whole of the Kenai Penmsula and the number of spe- 

 cies was very limited. A survey of the country, however, 

 readily explams their absence. 



The two main causes are the nature of the climate, and 

 the condition of the vegetation. The greater part of the 

 penmsula is subjected to conditions which render its climate 

 that of a temperate zone within a subarctic zone. The result 

 is that most boreal forms of mammals are excluded. Fur- 

 thermore, to the south rises a barrier which prevents the 

 migration of more southern species. For the coast south- 

 west of Prince William Sound (the southeastern boundary of 

 the Kenai Peninsula) is an almost unbroken chain of rugged 

 snow-capped mountains, cut by countless glaciers of great 

 extent — among them the Muir glacier, which is more than 

 sixty miles in width. The Kenai Mountams extend from the 

 western extremity of the peninsula to the barren grounds on 

 the east, thus forming an unbroken barrier which of course 

 prevents a movement to the Kenai region of species which 

 would naturally favor the conditions it presents. In any 

 event, the dense nature of the vegetation over the greater 



