124 Allen, Origin and Distribution of N. A. Birds. [^ p U r n 



t Charadrius d. fulvus Otocoris alpestris 



yEgialitis semipalmata Acanthis hornemanni exilipes 



♦yEgialitis hiaticula * Acanthis linaria rostrata 

 Arenaria interpres Acanthis linaria holbcelli 



Arenaria melanocephahis Plectrophenax nivalis 



Lagopus lagopus f Plectrophenax hyperboreus 

 Lagopus rupestris Calcarius lapponicus 



* Lagopus r. reinhardti Calcarius pictus 

 Falco islandus Anthus pensilvanicus 

 Falco rusticolus gyrfalco Saxicola cenanthe 



* Falco rusticolus obsoletus 



The following are arctic faunally, if not geographically, breed- 

 ing mostly above timberline in the Rocky Mountains : — 



Lagopus leucurus Leucosticte atrata 



Leucosticte tephrocotis Leucosticte australis 



Many other species, more properly Cold Temperate than Arctic, 

 range into the Arctic so that the above list is bv no means a com- 

 plete enumeration of the American Arctic avifauna. 



The North American Region (see PI. Ill) consists of two 

 Subregions, namely, (i) a Cold Temperate Subregion and (2) 

 a Warm Te?7tperate Subregion. The Cold Temperate Sub 

 region extends across the continent from about the mean latitude of 

 43 northward to the limit of forests, with also a narrow prolon- 

 gation southward along the Appalachian Highlands as far as 

 northern Georgia ; another in the interior along the main chain of 

 the Rocky Mountains and its principal outliers south into Mexico ; 

 and a third along the Cascade and Sierra Nevada ranges. Its 

 southern border also sweeps to the northward so as to exclude 

 the great Saskatchewan Plains. In other words, the Cold Tem- 

 perate coincides exactly with Dr. Merriam's 'Boreal Province' as 

 laid down on his 'Provisional Biological Map of North Amer- 

 ica'. 1 As compared with the Arctic, it has 120 genera instead of 

 65, of which about 70 per cent, are circumpolar, and 30 per 

 cent. American, showing the close connection of the life of the 

 whole northern half of the northern hemisphere. 



The following list of 213 species and subspecies includes only 

 such as may be properly considered as distinctively characteristic 

 of the Cold Temperate Subregion, as contrasted on the one hand 



' N. Am. Fauna, No. 3, 1891, map 5. 



