NOCTURNAL MIGRATION 43 



Swallows, swifts, and nighthawks feed as they 

 travel. Hawks and vultures are so large and robust 

 that fasting for a day or so is no hardship. Ducks 

 feed regularly by night, especially when there is 

 moonlight, and so are not hampered by the time of 

 day of their arrival. Such birds as shore-birds and 

 gulls must be able to endure without food, or must 

 curtail their journey when sustenance is required. 

 We must suppose that the same is true of migrants 

 among strictly nocturnal species like the goat- 

 suckers, of which our whippoorwill and chuckwills- 

 widow, and the nightjars of the Old World, are 

 familiar examples. 



Though among most small birds extensive flights 

 are made at night, the close observer soon becomes 

 aware of migration movement among them by day, 

 particularly during the period from the height to 

 near the close of migration. Flocks of warblers, 

 feeding seemingly without particular objective 

 through the tops of the trees, often pursue a regular 

 course in their search for food. Flights are made in 

 the direction in which the change of season is lead- 

 ing them. At times they travel hurriedly and must 

 cover an appreciable amount of territory during the 

 day. These movements may be noted with especial 

 ease at points where there are well-marked migra- 

 tion routes. At Point Pelee on Lake Erie, in the 

 autumn. Swales and Taverner have noted regular 



