CHAPTER LVII 



MIGBATION OP BIRDS 



'■' A T the approach of the cold season, "'Uncle Paul 

 l\. resumed, in his account of bird habits and bird 

 peculiarities, "before winter clears the fields of in- 

 sects, covers the ponds with a coating of ice, and 

 whitens the landscape with snow, thus cutting off the 

 food-supply hitherto obtainable from the earth, many 

 birds, especially those that live on insects or fre- 

 quent bodies of water and marshy meadows, take 

 leave of their native land and direct their course 

 southward, where they will find a warmer sun and 

 a more assured supply of food. 



"They take their departure, some in large flocks, 

 others in small groups, or even each one separately. 

 With no guide other than an irresistible impulse too 

 mysterious for us to explain, they traverse by suc- 

 cessive stages immense tracts of land, cross seas, and 

 bend their course toward the countries of the south. 

 Africa is the rendezvous of our birds and of Euro- 

 pean birds in general. 



"After the cold season has passed, with the first 

 fine days of spring the same birds return to the re- 

 gions where they were born, making the journey 

 this time in the opposite direction, from south to 



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