The Migration of Birds 189 



about half-past ten. Almost as quickly, there was a 

 decided increase in the number of call notes, and 

 dozens of birds came within the range of the light, 

 and several hovered about it, reminding one of large 

 moths before a flower. When the rain finally ceased 

 and the stars came out, the birds quickly ascended 

 into the higher regions. Toward morning there 

 seemed to be but a few stragglers, and before the sun 

 rose the wave had passed. 



Frequently lighthouses are so situated that they 

 afford excellent points for observation. Many times 

 birds fly against them and are injured or killed during 

 their night flights. It has been my experience to 

 find more frequently the yellow- or black-billed cuckoo 

 and vireos than other species killed by flying against 

 the tower. This would lead me to believe that they 

 do not fly so high as the others, or that they cannot 

 see so well to avoid objects. This observation has 

 extended over a period including twenty-four migra- 

 tions. 



The speed at which birds migrate is a subject beset 

 by many difficulties. There are several things to 

 be taken into consideration; such as, whether it is 

 the spring or fall migration, the first or the last part 

 of it, the climatic conditions, and the accessibility of 

 food. The average speed per day can be gotten at 



