274 TJ. S. NATIONAL MUSEUM BULLETIN 217 



Near Old Crow we saw a few hawks and geese flying as if in migra- 

 tion from the southeast. Lazarus Charlie recorded some arrivals of 

 land birds at Johnson Creek, on the Porcupine 80 miles southeast of 

 Old Crow, before we saw them. These observations suggest that 

 some eastern birds reached the Porcupine by flights northwesterly 

 from the Mackenzie Valley. We have no clear evidence whether 

 the Porcupine is an important migratory route for small eastern birds 

 on their flights toward Alaska, but the Peel Eiver breaks through 

 the southern Kichardson Mountains in low passes which, from their 

 appearance on the map, would be favorable routes from the Mac- 

 kenzie to the Porcupine Valley, so I suspect that eastern birds, and 

 possibly some eastern components of the western migrations enter 

 by this course. 



For birds from the westernmost United States to reach western 

 arctic Alaska requires a westerly flight over at least 40 degrees of 

 longitude. Birds arriving in arctic Alaska from the Mississippi 

 Valley must have traveled 70 degrees westerly and some golden 

 plover {PJ/uviaUs dominica) when southbound from Alaska to Nova 

 Scotia must traverse 100 degrees of longitude easterly in order to 

 clear the Atlantic coast on their overwater flight to South America. 



The 45 species of birds which migrate over land through North 

 America must pass westerly from at least 30 to more than 70 degrees 

 on their flights to arctic Alaskan breeding grounds. The amount 

 of westing involved may be seen by comparison with that of about 

 100 degrees from San Francisco to Manila. The changes in local 

 time at solar noon encountered by the migrating golden plover 

 (PluviaUs) during a few weeks of late summer is comparable in 

 rate and hours to that during a voyage by ship across the Pacific Ocean. 



The Asiatic wintering birds (table lid) reach western Alaska by an 

 as yet undefined oversea route from Siberia. Since in eastern Alaska 

 they are concentrated in its northern and arctic parts, I suspect that 

 they cross Bering Strait. 



It may seem that these Asiatic wintering species make only a feeble 

 penetration into the American continent, but they are not always 

 easy to see, and they occupy secluded haunts within untraveled areas. 

 In my experience, with the exception of the bluethroat {Luscinia), 

 they are numerous and widely distributed. Although their hold upon 

 the American continent has been regarded as tenuous, actually they are 

 established in Alaska by easterly migrations as impressive as those of 

 any American wintering birds. If the wheatears {Oenanthe) which 

 nest in eastern Alaska come from the central wintering area for the 

 race in Arabia (Mackworth-Praed and Grant, 1951) their spring 

 migration passes halfway around the world. Ascribing to them the 

 most easterly winter residence possible in China, they would still have 



