Pilgrims of the Night 



unearthly quality. This fact has led some 

 writers to query whether there may not be 

 a universal migratory call among the birds 

 of the air, familiar to and understood by all 

 species of songsters, as a sort of rallying 

 cry or exchange of greetings just as men 

 of all races use salutations that are so much 

 alike as to be perfectly intelligible every- 

 where. 



Be this as it may, we can evidently rely 

 little upon the migratory cries of birds as 

 a means of identifying species; and, as I 

 have said, the flights being chiefly by night, 

 and at a considerable distance above the sur- 

 face of the earth, it is equally impossible to 

 identify the various species of migrants by 

 sight. The only way we can trace the 

 courses of these flights, in spring and au- 

 tumn, and determine the species of which 

 they are composed, is to watch for the birds 

 as they descend to earth in the daytime to 

 rest and feed, and then compare records 

 with other observers all along the line. 

 Even in this way we do not get very accu- 

 rate information of routes and dates of ar- 

 rival, because there is always more or less 

 confusion arising from the presence of par- 



57 



