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THOMAS SADLER ROBERTS 



United States to spend the winter, and of these all the individuals 

 of 26 species go all the way to the plains, forests, and mountains of 

 South America, making this long and hazardous round trip annually 

 in response to an imperative instinctive habit (or "physiological 

 prompting") implanted in them by conditions existing in ages now 

 long past. Within an area including the southern portion of the 

 eastern United States, Mexico, Central America, the West Indies, 

 and northern South America may be found during the winter time 

 some 113 other species of Minnesota birds that are spending the 

 northern cold season in these more hospitable climes. Thirty-six 

 species do not extend their journeyings beyond the southern tier 

 of states, and are ever ready to return to the Northland with the 

 first indications that forbidding Winter has released his icy grip. 

 These latter birds constitute our early spring arrivals. The more 

 southern-wintering species come later and make their appearance 

 about the same time each year, no matter what the seasonal 

 conditions may be. 



Young Cooper's Hawks 



