ROUTES OF MIGRATION. 107 



migration passes along the shores of these vast 

 inland sheets of water. There is much evidence 

 to show that the noble St. Lawrence is a fly-line 

 of many northern Nearctic species ; whilst further 

 south the stream of migration is carried along the 

 various valleys of the Mississippi, Missouri, and 

 Ohio. These latter to a great extent carry off the 

 migrants of the United States between the Rockies 

 and the Alleghany Mountains. The migrants 

 from the east of these latter mountains appear to 

 follow the numerous streams that lead to the 

 Atlantic coast-line ; whilst those from the west of 

 the Rockies follow similar streams to the Pacific 

 coast. 



Our knowledge of the ornithology of South 

 America is so meagre in its details that we have 

 next to no data on which to form an opinion as 

 to the value of river valleys as highways of migra- 

 tion. There cannot, however, be much doubt that 

 such favourably-placed valleys as those of the 

 Parana, the Paraguay, and the Uruguay, trending, 

 nearly due north and south for 1500 miles, have a 

 very important influence on migration iu the wide 

 districts which they aflect. 



That migration follows these great inland valley 

 routes is abundantly proved by what has actually 

 been observed in them. Wherever competent 

 observers have noted the seasonal movements of 

 birds along them, the facts are essentially the 

 same. Down all these great valleys Migration ebbs 

 and flows in no uncertain trickling stream, but in 



