272 U. S. NATIONAL MUSEUM BULLETIN 217 



(1852, p. 124) saw the geographical relations of the Mackenzie Valley 

 in a manner different from Dall, for he remarked, "On the Mac- 

 kenzie there is an intermingling of the flora of both coasts, as 

 well as of the migratory feathered tribes, the Rocky Mountains not 

 proving a barrier to either." Actually Dall's view, limited to Alaska 

 and overemphasizing the eastern character of the fauna properly 

 accentuated the remarkable trend of bird migration in northern North 

 America to the westernmost parts of northern Alaska and even into 

 Siberia. This westerly trend in migrations is undoubtedly related to 

 conditions produced by the east-west direction of mountains and 

 valleys in Yukon and northern Alaska. 



The very complexity of the terrain of southern Yukon and Alaska 

 leads me to believe that, although we now have few significant obser- 

 vations of northern routes of migration, we can by reasonable specu- 

 lation predict the situations in which these routes may be discovered. 

 It is my belief, based upon observation in northern Alaska, that the 

 high mountains of the coastal and Alaska ranges must funnel much 

 of the migratory bird traffic through the few low passes by which the 

 cold and barren high elevations can be avoided. 



Some of the maritime birds wintering on Pacific American coasts 

 (table 10) must leave the Gulf of Alaska to pass overland to the 

 Porcupine Valley, where a number of these species were seen arriving 

 at Old Crow from the west (see p. 157) . Their crossing of the Coast 

 Range may be suspected to start its overland passage east of the high 

 St. Elias Mountains. Westward along the Gulf of Alaska the next 

 break in the lofty Coast Range is through the Copper River Valley, 

 which in its lower part is still raw from the recent retreat of great 

 glaciers. Further west the Susitna Valley opens from Cook Inlet 

 and leads northward, as does the Copper Valley, to passes through 

 the Alaska Range into the Tanana Valley. From Cook Inlet, also, 

 Rainey Pass leads through the Alaska Range west of Mount McKinley 

 to the Kuskokwim Valley. Some of the maritime birds wintering 

 along the Alaska Peninsula and Aleutians probably cross and round 

 the Peninsula. These routes are postulated from a few records of 

 migration but mainly from geographical appearances and as sug- 

 gestions for a strategy of further observation. 



A few of the maritime species (table 10) which winter on south- 

 western Alaskan coasts probably pass from Bering Sea eastward 

 along the Yukon, for Dall (Dall and Bannister, 1869) remarked upon 

 the early arrival of goldeneyes {Bucephala clangula) at Nulato from 

 the west. According to Dall they winter extensively in the Aleutians. 

 Mary Lobban informed me that late in October 1957 goldeneyes were 

 numerous about Cold Bay, near the western end of the Alaska Penin- 

 sula. Since much of their nesting area lies east of Alaska the west- 



