2IO THE MIGRATION OF BRITISH BIRDS 



work accomplished by the British Association, respect- 

 ing the information collected by its committee con- 

 cerning Migration in the British Archipelago. But one 

 of the most important points of observation has been 

 entirely neglected. I allude to the complete absence 

 of information respecting migration between the Start 

 Lighthouse in Devonshire and the Varne Light-vessel at 

 the mouth of the Strait of Dover — the most interesting 

 stretch of coast-line throughout the entire British Archi- 

 pelago. Concerning the internal routes followed by 

 migratory birds, our information is still more meagre. 

 We now want a thousand recording stations in inland 

 districts, with observations extending at least over a 

 period of five years before we can obtain sufficient 

 material to suggest very minutely the probable lines of 

 migration within the British Area. This need be no 

 difficult task, all that is required being the earnest 

 co-operation of ornithologists. In the present chapter, 

 therefore, I cannot treat the subject so fully as I desired ; 

 but I think we have sufficient material in our possession 

 to suggest some very important facts. 



In the first place, it may serve to simplify matters if 

 we endeavour to explain What a Route of Migration is, 

 and How it has been formed. The following remarks, 

 be it clearly understood, apply as much to British species 

 as to species in all other parts of the world ; and the 

 facts set forth must be constantly borne in mind by the 

 student of Avian Dispersal and Migration. In the first 

 place, then, wc may remark that a bird's breeding 

 grounds and its winter quarters were once continuous, 

 no matter how remote one may now be from the otlier. 

 The Northern Emigration has slowly progressed purely 



