OUR RARER BIRDS 



A word now as to the purpose of Migration. Migration 

 is undoubtedly undertaken for the purpose of obtaining 

 a necessary supply of food. Those birds that migrate must 

 either do so or starve. The Swallow and the Cuckoo, 

 and the army of soft-billed birds that come here with the 

 summer, would doubtless remain here if food were always to 

 be had ; but the moment the supply fails in autumn, back 

 they go to lands where insect-life is plentiful and winter is 

 unknown. 



Birds pursue certain routes to and fro which it has doubt- 

 less been their custom to follow ever since the habit of 

 migration was acquired. These still continue to be traversed, 

 even though the practice involves a journey of many hundreds 

 of miles farther than is actually required 1 Tor instance, 

 many of the birds that migrate from Norway and Sweden, 

 and even from Northern Eussia, cross to our islands over the 

 wild North Sea, instead of keeping to the continental coast- 

 line. Others travel to certain winter quarters in remote 

 parts of the world, from ignorance of the way to those much 

 nearer and in every way suited to their requirements. Thus 

 the Eustic Bunting and the Arctic "Willow Wren come every 

 summer as far west as Scandinavia, but return every autumn 

 to India, China, and even the remote Malay Archipelago; 

 and on the other hand, the Eed-footed Falcon (a bird which 

 has occasionally been met with in the British Islands), which 

 breeds as far east as Central Siberia, is only known to winter 

 in Africa 1 The wonderful interest attaching to these extra- 

 ordinary migrations can only be fully realised when the 

 routes of these little birds are traced upon a map. The ex- 

 planation of these singular movements is to be found in the 

 fact that when these birds were driven southwards by the 

 glacial epoch, they sought shelter in the countries to which 

 they still unerringly return, although, since they have been 

 able to get back north again, they have increased their 



