752 THE AMERICAN NATURALIST. [Vor. XXXVI. 
. When a migratory flight of hawks takes place, continued 
favorable winds exhaust the number of hawks ready to make the 
migratory journey, but a second favorable wind about one week 
later may cause a second flight equal in magnitude to the first. 

Map IV.—Coast LINE OF SOUTHERN NEW ENGLAND, NEW JERSEY, AND 
DELAWARE 
The long arrows indicate «ms direction of migration of hawks and various other birds in the 
spring, when the wind is west or southwest. Owing to the fact that the coast line is 
nowhere at right ang o the direction of migration, the flight is not in a narrow 
emet as along the Cometic shore in autumn, but ten or fifteen miles wide in the 
m part of New Jersey. 
The arrows marked A = a "e up the Hudson enya -- marked Z a flight up the 
Housatonic valley i and those marked eneral northeast flight in New 
England. The haies range, along which many leoi s migrate, is indicated by D. 


8. That a favorable wind, when the favorable component is 
small, may cause decided deviations of the course of the migrat- 
ing birds from the main migratory direction. 
