ROUTES OF MIGRATION 



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highway of migration which crosses the southern Alleghanies from 

 northwest to southeast. This is evidently followed by Kirtland's 

 Warbler, which nests in northern Michigan and winters in the Bahamas, 

 and it brings to our southeast Atlantic Coast, with more or less regular- 

 ity, birds which are practically unknown in our North Atlantic States. 



FIG. 8. Migration of the Redstart. A species which breeds throughout the 

 greater part of temperate North America, and migrates through the West Indies, 

 Mexico and Central America. 



Dotted area Breeding range. Black area Winter range. Arrows Migration 

 route. 



There are also minor routes or paths of migration formed, generally, 

 by favorable local conditions, but in some instances difficult to explain. 

 I have seen Tree Swallows, in the spring, on the Gulf coast of Florida, 

 migrating northward low over the great expanse of unbroken marshes, 

 but evidently following a definite track. The scattered flocks were 

 often separated by several miles, but each one followed in the wake of 

 its invisible predecessor as though guided by the marks of wing- 

 beats in the air. 



