34 £be Warbler 



yet involved in some obscurity. A vast number of northern Warblers and 

 Flycatchers do not pass over the low countries of Carolina in their migra- 

 tions, and the closest observers have not been able to find a single specimen 

 of many species that are abundant in the North and that all migrate south- 

 erly in autumn. It is possible that migratory birds pass southerly in two 

 immense channels, one leading from Hatteras or some of our Capes a little 

 farther south, and thus across the Gulf of Mexico to the West India Islands, 

 where they spend the period of our winter in immense numbers. They are 

 often met at Sea during the periods of their migrations and are frequently 

 known to light on the rigging of vessels where they rest for an hour or two, 

 and then again pursue their onward course. The other path of migration, 

 and probably the most common, to which I referred, is along the Allegany 

 and that vast chain of Mountains which extend throuo-h the 

 whole interior of our country. I infer this to be the case, since the Rose- 

 breasted Grosbeak, the Baltimore Oriole, the Scarlet Tanager and a number 

 of species of Warblers, that seldom visit the maritime districts of Carolina, 

 are found to pass along the Mountains of Carolina and through the states of 

 Louisiana, Mississippi and Arkansas. Some of these birds remain in Mex- 

 ico, some enter within the Tropics and others in all probability pass beyond 

 them in order to find a climate similar to that which they have left. It has 

 recently been ascertained that some birds that are found in the north of 

 Europe, and have hitherto not been known to exist in America, migrate 

 from the Polar regions along the Rocky Mountains into Mexico and leturn 

 by the same way in their spring migrations. The Magpie (Corvus pica), and 

 the Bohemian Wax-wing (BombvciUa garruld) are of that number. Several 

 other birds peculiar to the American Continent never visit the cultivated 

 districts of the United States, but take the chain of the Rocky Mountains in 

 their annual migrations. Among these are the Cinclus mexicanus, the Eve- 

 ning Grosbeak {Fringilla vespertina), Clark's Crow (Corpus columbianus). The 

 Columbia Jay, a most splendid bird figured by Audubon, nearly rivalling in 

 beauty the Bird of Paradise. 



The spotted Thrush of Latham (Turdus naevius), the Arctic Bluebird 

 (Ervfhaca arcfica) , the Ember iza picia, and the saffron-headed Troupial (Icterus 

 xanthocephalus) are also of this num ber. 



The course of migration of American birds is generally from North to 

 South, varying somewhat so as to follow the range of mountains and the 

 course of rivers. Those only that breed in the Arctic circle visit both Con- 

 tinents. It is computed that out of about 450 species already known in 

 North America only twenty-seven land, and thirty-one water birds are na- 

 tives of both Continents. Consequently 342 species are peculiar to our 

 Continent. The land birds that visit Europe are composed of Eagles, 

 Hawks, Owls and a few other species possessing great strength of wing, and 



