Migration Flights 35 



A study of the records of these 63 days readily shows that 

 they include the heaviest of the bulk movements of many 

 species as well as the " firsts " of others. 



In view of what has preceded there seems to me ample 

 justification for the statement that in Central Illinois there is 

 a high degree of correlation between the flights of night 

 migrants and the meteorological conditions involved in the 

 near approach from the West of an area of low barometric 

 pressure with the accompanying rise in temperature and south- 

 erly winds. 



A preparation of graphs showing temperature changes and 

 migration activities would doubtless show marked correla- 

 tion, as have those prepared by Stone at Philadelphia. So 

 also would graphs showing changes in the wind and migra- 

 tion activities. The determination of the relative importance 

 of temperature and wind direction in the initiation of the 

 separate migratory flights is yet to be made. 



