Migration Routes 41 



they turn back east to the point in Siberia whence they came, before turning 

 southward to spend the winter on the borders of India. 



Forty or more species of migratory birds occur as summer residents in the 

 Yukon Basin, Alaska. Of these some fourteen species are Pacific coast birds. 

 With a single exception they are all thought to reach the upper Yukon by cross- 

 ing the Alaskan coast range of mountains. This exception, according to Mr. 

 W. H. Osgood, of the U. S. Biological Survey, is the Varied Thrush (Hesperocichla 

 ncevia}, which apparently reaches its summer home by going up the coast to the 

 lowlands below the mouth of the Yukon, and thence follows this river for 

 almost 2000 miles. Equally abundant with it in this summer home is the 

 common Snowbird (Junco hyemalis) of the eastern United States, which reaches 

 the Yukon Basin by way of the Mississippi Valley. 



Perhaps the longest straight-away flight made during the migrations is ac- 

 complished by certain shore and water birds, as the Tattler (Heteractitis incanus), 

 Sanderling (Calidris arenaria) t Turnstone (Arenaria interpres), and the Pintail 

 and Shoveler Ducks, which nest on islands in the Bering Sea and spend the winter 

 in the Fanning and Hawaiian groups, a distance of some 2200 miles. As the 

 shore birds above enumerated are probably unable to rest on the surface of the 

 water, the entire distance must be accomplished in a single flight. It is difficult 

 indeed to see how this line of migration could have been established. Following 

 the analogy of the Old World species before mentioned whose path marks an 

 ancient shore-line, we might presume that there was at one time a land connec- 

 tion, or at least a chain of islands, between the Aleutian and Hawaiian groups, 

 but on the contrary the depths of the Pacific are profound between these points, 

 and there is not the slightest geological evidence on which to base a former land 

 connection. When it is recalled how slight a deviation at the point of departure 

 would suffice to throw them to the one side or the other of the Hawaiian Islands, 

 the accomplishment is truly marvelous. In the absence of familiar landmarks 

 and surrounded by a waste of sky and water, they make their way with the pre- 

 cision of a rifle bullet. 



The Plovers, Sandpipers, and kindred species take migratory journeys often 

 of extraordinary length. Thus the American Golden Plover (Charadrius domini- 

 ons} breeds in Arctic America, some venturing a thousand miles north of the 

 Arctic Circle, and migrates through the entire length of North and South America 

 to its winter home in Patagonia, and curiously the spring and fall routes are very 

 different. After feasting on the crowberry in Labrador they seek the coast of 

 Nova Scotia, where they strike straight out to sea, taking a direct course for the 

 easternmost islands of the West Indies, and thence to the northeastern coast of 

 South America. In spring not one returns by this route, but in March they appear 

 in Guatemala and Texas. " April finds their long lines trailing across the prairies 

 of the Mississippi Valley; the first of May sees them crossing our northern boun- 

 dary, and by the first week in June they reappear in their breeding grounds in 

 the frozen North." The little Sanderling just mentioned is almost cosmopolitan 

 in distribution, breeding in Arctic and sub-Arctic regions and migrating in the 

 New World to Chile and Patagonia, a distance of 8000 miles, and in the 



