lOO Brewster oii the Biiuh of Western North Carolina. [January 



accurately on the map the I'elative extent and position of the three 

 faunte by using- a different color for each, as, for instance, green 

 for the Canadian, red for the Alleghanian, and white for the Car- 

 olinian, the work when completed would certainly present a 

 strangely patched appearance. Probably the white would pre- 

 dominate in extent, with red next, and green last. 



The boundaries between the different faunal areas are sharply 

 marked in places, in others only faintly so, one set of birds often 

 overlapping and mingling with another throtxghout a belt of neu- 

 tral ground. The line of separation between the Canadian and 

 Alleghanian divisions, so far as I observed, is better defined than 

 that between the Alleghanian and Carolinian. Tlie Canadian 

 Fauna is also purer than either of the other two. Thus on Black 

 Mountain, at about 5000 feet, I found only three species { Parus 

 carol iiiensis, CatJiartes aiira^ and Colinus vi^-giiiiajnis) which 

 are not common and more or less characteristic forms of the 

 Canadian Fauna of New England ; \vhereas double this luunlier 

 of Carolinian forms extended upward into Alleghanian areas, 

 and as manv more Alleghanian birds downward over Carolinian 

 territory. The lowest vallevs of all possess a few Louisianian 

 species, such as Dcndroica doniinica and Penccea bacJimani ; 

 but this infusion is too inconsiderable to be of much practical im- 

 portance. 



An interesting feature, more or less noticeable in each of the 

 three faimal divisions just mentioned, is the unusual restriction 

 of certa-in species and the general distribution of others. Thus 

 Deiidroica blackbiirnice and D. ccerulescens^ elsewhere mainly 

 confined to the Canadian Fauna, were here found in equal or 

 even greater abundance over most of the Alleghanian, Parus 

 carolinensis, LopJiophanes bicolor^ and Seiiirits tnotacilla 

 ranged from the lowest vallevs nearly to, and in some cases 

 actually above, 4500 feet ; while Dendroica virens. in the North 

 common alike to the Canadian and Alleghanian Fauna?, was met 

 with only in the ' balsams ' at high elevations on the Black 

 Mountains. 



With, these and a few similar cases it is evident that altitude 

 plays onlv a secondarv part, various iocal conditions — such as the 

 presence or absence of certain trees or shrubs — having clearly 

 more influence. Dendroica virens^ for example, was seen only 

 where spruces and balsams predominated over other trees, and 



