20 



BULLETIX 185, U. S. DEPARTMENT OF AGRICULTURE. 



central California, wiiere it becomes common before the first arrivals are usually 

 noted in Texas or Florida. The route the species takes from Brazil to California is 

 one of the yet unsolved migration puzzles. 



Since the above was written much additional information has been 

 obtained on the movements of this species, and now it is possible to 



BREEDING RANGE 



WINTER HOME 



Migration routes of Ar'antic wintering birds 



Known port of migration route of Rrciric winTe ring birds 



Supposed migration route of Pacific wintering birds 



Fig. 8. — Distribution of the white-winged scoter (Oidemia deglandi). Birds wintering on the Atlantic 

 coast follow an elliptical migration route, passing eastward in fall to the Labrador coast and returning 

 the following spring by a route from Long Island Sound northwestward directly to the breeding grounds. 

 Birds wintering on the Pacific coast are known to migrate spring and fall along the coast between Wash- 

 ington and southern Alaska, but where they cross the mountains can only be surmised, for they have 

 never been noted anywhere on the 500-mile strip between the Pacific Ocean and the Mackenzie River, 

 and apparently this part of the migration route is accomplished at a single flight. (See p. 21). 



solve this migration puzzle. It is now known that the cliff swallows 

 go around the Gulf of Mexico instead of across it. The isochronal 

 lines on the migration map show that the birds advance along the 

 Pacific coast of Mexico faster than along the Gulf side, so that on 

 March 20, when the van has not quite reached the lower Rio Grande 

 of Texas, it is alreadv far north in California. 



