CHAPTER VIII 



WEATHER INFLUENCES : THE METEOROLOGY OF 

 BIRD-MIGRATION ^ 



It has lonq;' been realised that birds are extremely sensi- 

 tive to atmospheric conditions, and that they discern 

 approaching meteorological changes. It is on this 

 account that in popular weather-lore, the sayings and 

 proverbs based upon the actions of these feathered baro- 

 meters are so exceedingly numerous ; and probably 

 many of them date from Roman times. 



Migratory birds are specially influenced, since their 

 movements are undoubtedly correlated at all seasons 

 with the weather, which has a controlling effect over 

 their performance, either as an incentive to embark upon 

 their aerial voyages, or as the greatest of barriers to 

 their performance. 



A knowledge of the meteoroloQ['ical conditions associ- 

 ated with bird-movements is extremely important, and 

 I have often found it to contribute in a remarkable way 

 to an interpretation of their precise nature. 



When studying the meteorological aspects of bird- 



1 It has been my good fortune to have the meteorological statements 

 made in this chapter verified by W. N. Shaw, Esq., LL.D., D.Sc, F.R.S., 

 etc., the Director of the Meteorological Office, in accordance with whose 

 criticism and advice it has been amended. I desire to acknowledge fully 

 Dr Shaw's most valued assistance. 

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