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 Dakota, 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 Mountain region. Such birds perform comparatively short migrations, most of them being content to stop when they reach the middle districts 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 fly way. 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