ILLINOIS AUDUBON SOCIETY 



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these migration nights with the consequent changes in the bird population 

 are going on actively during the greater part of the year. In central 

 Illinois, the arrival of birds from the south usually begins in February 

 and often before the middle of the month. From this time on for nearly 

 four months there is a continually shifting population, and not until some- 

 time in June have the last migrants that hail from South America, taken 

 their departure for more northern regions. In August the return journey 

 is under way and birds on their way to the South American winter quarters 

 are again with us for a brief time. Not until December have the last 



