THE MIGRATION OF NORTH AMERICAN BIRDS 47 
terest to note that while some other geese and many ducks start their 
northward journey at the first sign of awakening spring, the blue 
goose remains in its winter quarters until the season there is far 
advanced, seemingly aware that its own breeding grounds in the 
Arctic are still in the grip of winter. 
As shown by the route map (fig. 21) a great western highway also 
has its origin in the Mackenzie River delta area and in Alaska. This 
is used chiefly by the pintail and the baldpate (Vareca americana), 
which fly southward through eastern Alberta to western Montana. 
Some localities in this area, as for example, the National Bison Range, 
at Moiese, Mont., normally furnish food in such abundance as to in- 
duce these birds to pause in their migratory movement. Upon re- 
suming travel, some flocks move almost directly west across Idaho to 
the valley of the Columbia River, from which they turn abruptly 
south to the interior vaileys of California. Others leave the Montana 
feeding and resting areas and turn southeastward across Wyoming and 
Nebraska to join the flocks that either are moving southward through 
the Great Plains, or are to continue across Arkansas to the main 
Mississippi Valley flyway. 
Many redheads that breed in the Bear River marshes in Utah, 
take a westerly route across Nevada to California, but some leave 
these breeding grounds and fly northeastward across North Dakota 
and Minnesota to join the flocks of these ducks that come out of the 
prairie regions of Canada, and travel southeastward to the Atlantic 
coast. This route can be well traced by the records of ducks banded 
in summer in the Bear River marshes and retaken the following fall 
at points in eastern Montana, Wyoming, South Dakota, North Da- 
kota, Minnesota, Wisconsin, Michigan, and Maryland. 
Another route from these great marshes crosses the mountains in 
an easterly direction, but almost immediately turns southward 
through Colorado and New Mexico, and continues to winter quarters 
in the Valley of Mexico (fig. 21 and fig. 20, route 6). This route also 
represents the travels of many of the land birds of the Rocky Moun- 
tain region. Such birds perform comparatively short migrations, 
most of them being content to stop when they reach the middle dis- 
tricts of Mexico, only a few passing east beyond the southern part of 
that country. 
This account of the Mackenzie Valley—Great Lakes—Mississippi 
Valley route shows the great importance of this highway and also its 
complicated nature. It receives accretions from both the northeast 
and the northwest, while branch routes make wide detours toward 
the Pacific coast before turning back to the parent flyway. This 
flyway is notable for its great length, as it extends from the Arctic 
coast to Patagonia; and for its width east and west, as in North 
America it reaches from the Allegheny Mountains westward to the 
Great Basin. 
PACIFIC COAST ROUTE 
Although it does present features of unusual interest, the Pacific- 
coast route is not of so great importance as some of the others de- 
scribed. Because of the equable conditions that prevail, many species 
of birds along the coast from the Northwestern States to Southern 
Alaska either do not migrate at all or else make relatively short 
journeys. This route has its origin chiefly in Alaska, the general 
region of the delta of the Yukon River marking its northern terminus, 
