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frequent utterance of their call-notes on days which precede 

 nights of strong migrations." It may, perhaps, be readily 

 admitted that the power of foretelling some twenty-four hours 

 ahead, approaching changes which will affect the weather locally 

 is possessed by the great majority of birds, and we can easily 

 understand how such a faculty has been acquired through the 

 process of natural selection. But is there any evidence to show 

 that this faculty is operative from the surface of the earth in a 

 vertical as well as a horizontal direction ? All changes in the 

 weather, according to the author, becoming first evident in the 

 higher regions of the air. The fluttering of a captive bird of a 

 migratory species on days preceding strong movements, may point 

 to nothing more than the periodically recurring impulse which 

 must be inherent in all such species. If we attribute this rest- 

 lessness, however, to a knowledge of a change in the atmosphere 

 which will bring about an abnormal migration abnormal both in 

 strength and character then we must assume that this sense, 

 which enables the captive to perceive the coming change, is only 

 operative at times corresponding to the usual periods of flight, 

 otherwise we should expect a similar exhibition of restlessness at 

 every coming change in the atmosphere. In the face of this 

 contention it seems more reasonable to attribute this restlessness 

 to inherited desire to migrate becoming active at these particular 

 times. If we grant that birds have the power of discerning the 

 state of the weather in the countries ahead of them, we can only 

 wonder why so many come to grief in performing their migration 

 prematurely. That this often happens there is abundant evidence 

 to show. Mr. Seebohm's experience of this premature migration 

 in the Valley of the Yenesay is a well-known instance. With 

 regard to Herr Gatke's remark that the sensitiveness of birds to 

 the first faint indications of an atmospheric change must be at 

 least equal to that of a good barometer, this may, perhaps, be 

 granted, as it is no uncommon thing to meet with human beings 

 who are able to predict with constant accuracy the state of the 

 weather for the coming twenty-four hours. This is accomplished 

 with no other aid than their natural senses. However, Herr 

 Gatke adds that f< we must not forget that in the elevated 

 regions in which their migrations proceed, birds are brought under 



