°g" Loomis on Birds of Chester County, South Carolina. 113 



In winter, as has been seen, there are physical conditions that 

 force birds southward, which birds are prompt to recognize, and 

 in autumn physical conditions that serve at least to admonish that 

 it is time for the journey south to begin. In the summer move- 

 ments, however, such incentives are wholly wanting. The 

 pressure of migrants from further north, however potential it 

 may be in some stages, is lacking in the first movements. How, 

 then, does this adaptation to the necessity for early migration come 

 about? Is the cause a mere blind impulse, inherited from 

 ancestors? or is it the result of education, indirect from example, 

 or direct through special instruction ? Birds perform long 

 journeys, following the outlines of landscape, occupying the 

 same regions season after season with such regularity that life 

 areas are defined with certainty. They adjust their winter move- 

 ments to the ice and snow, and meet exceptional conditions by 

 exceptional migration. These facts, indicating as they do that 

 birds possess a high degree of intelligence, are incompatible with 

 the theory that mere blind impulse is the cause of migration. 



The conduct of wild birds in confinement, procured when 

 young, was long ago pointed out by Dr. Bachman in his essay 

 on migration (Amer. Journ. Sci. and Arts, XXX, 1S36, p. 96) 

 as evidence of inborn impulse. The spirit of restlessness spoken 

 of may have been aroused, however, by the presence of other 

 birds that were migrating at the time. Further, wild birds in 

 captivity do not always exhibit such restlessness, as is attested by 

 Mr. Watkins in the Evening Grosbeak (Jide Butler, Auk, X, p. 

 157). Audubon says (Orn. Biog. Ill, p. 9) of a female Canada 

 Goose raised from an egg taken from a wild bird, "At the period 

 of migration she shewed by her movements less desire to fly oft' 

 than any other I have known ; but her mate, who had once been 

 free, did not participate in this apathy." This species has 

 become a 'classic' illustration of the alleged awakening of an 

 irresistible desire for migration with the return of spring. It is 

 now well established that there is continual migration in this and 

 other species during the colder months, there being no sudden 

 arousing of migratory impulse in their case at least. In mild 

 autumns the later migrants delay their journey, lagging by the 

 way, evincing that the impelling force in the continuance of their 

 migration is from without and not from within. Still these facts 

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