28 PROCEEDINGS OF THE ACADEMY OF [1893. 



by him as limited thereto, ten : — Dendragapus obscurus fuliginoms, 

 Bonasa umbellm sabini, Megascops a*!o kennlcottii, Bubo virginianus 

 saturatus, Colaptes cafer saturatior, Junco hyemalis oregonu*, Melospiza 

 fasciata guttata, Troglodytes hiemalis paeificus, Regulus satrapa oliva- 

 ceus and Tardus aonalaschkce, are represented in various localities 

 between and including the Cascades and the Rockies. Of those 

 restricted by him to territory east of the Cascades, Dendragapus 

 franklinii, Bonasa umbellus togata, Bubo virginianus (7), Falco pere- 

 grinus anatum, Falco columbarius, Ammodramus sandwichensis alau- 

 dinus and Sijlvania pusilla, are also found west of them. 



It is thus seen that coast and interior species overlap across wide 

 areas. This is probably due less to migration than to isolated 

 reproduction of eastern and western environments in alternate sec- 

 tions of country induced by altitude, the Japan current, prevailing 

 winds, parallel and intervening mountain ranges and the projection 

 of an arid Transito-Sonoran area, 200 miles wide and 100 long, 

 into the midst of the southern section of the Province. I am 

 nowise convinced that we are to look east or west for an annual 

 supply of those birds assigned to so-called " eastern or western 

 races " Avhich are found in out-of-the-way or unlooked-for localities 

 in British Columbia. On the contrary, it is probable they are the 

 native born product of similar isolated environments and, while of 

 the same ancestral stock, have become so isolated by changes in the 

 climate and topography of intervening territory. In other cases 

 they will be found, by a more thorough exploration of the country, 

 to be connected with the type habitat by narrow lines of distribu- 

 tion, projecting south and west from Alaska and Great Slave Lake 

 and east and west through the low passes of the Cascades and 

 Northern Rockies. Such aspects of distribution have little to do 

 with the mere annual north and south movement which we call 

 migration ; evolution of environment and evolution in accord with 

 environment are the responsible factors. These have made possible 

 the occurrence of Spizella socialis on Vancouver Island and of Bubo 

 virginianus saturatus in Labrador, each represented over a vast 

 intervening territory by a distinct race. The migration of eastern 

 forms resident in southern British Columbia is undoubtedly over an 

 independent Great Basin route and not, as Mr. Chapman surmises, 

 along the western edge of the Great Plains. 



To Edwards Bros, of Tacoma, Mes-rs Fannin, Maynard and 

 Lindley of Victoria, the Messrs McKinley of Lac La Hache, and Mr. 



