MIGRATION. 171 



is as familiar to the latest Nile-boat traveller or 

 dweller on the Bosphorus as of old to the 

 author of the Book of Job. The autumnal 

 thronging of myriads of water-fowl by the rivers 

 of Asia is witnessed by the modern sportsman 

 as it was of old by Homer. Anacreon welcomed 

 the returning swallow in numbers which his 

 imitators of the colder north, to whom the 

 association connected with it are doubly strong, 

 have tried in vain to excel. The Indian of the 

 fur-countries, in forming his rude calendar, names 

 the recurring moons after the birds-of-passage 

 whose arrival is coincident with their changes. 

 But there is no need to multiply instances. The 

 flow and ebb of the feathered tide has been sung 

 by poets and discussed by philosophers, has 

 given rise to proverbs and entered into popular 

 superstitions, and yet we must say of it still that 

 our ' ignorance is immense.' " 



We may however take " heart of grace " for 

 this pile of ignorance is being slowly demolished ; 

 and the traditions, legends and superstitions, 

 of which it was made up, are being slowly 

 consumed by the fire of criticism. As a result, 

 we can now class the observed phenomena under 

 three heads and speak of (1) accidental migrants, 

 (2) birds-of-passage, and (3) migration proper. 



As this last is the most important and the 

 most typical, we will discuss it first. This section 

 then treats of the periodic movement of large 

 bodies of birds from one place to another, often 

 thousands of miles apart. 



Concerning migration proper, we have learnt 

 this — that species which winter with us, leave in 



