CHAPTER XIV 



MIGRATION 



THE study of the migration of birds bristles with difficulties, even 

 when prosecuted under the most favourable circumstances. Yet 

 even the teacher in large towns may find some evidences of the 

 periodical arrival and departure of different species of birds. 

 Starlings and the thrush tribe will afford the readiest examples ; 

 but even in large cities like London many species are met with 

 during the spring and autumn that are seen at no other time in the 

 year. In Battersea Park, London, for instance, no less than 

 thirty species of birds have been met with by the writer during 

 the last year or so in a wild state. And among the more interest- 

 ing of them may be mentioned the wheatear, redstart, whinchat, 

 wren, yellow wag-tail, spotted flycatcher, swallow, and house- 

 martin, swift, nightjar and common sandpiper. In the nature 

 of things these birds cannot breed here, but appear suddenly and 

 as suddenly vanish during the spring and autumn months. 



But we know that ten miles out of London all these birds may 

 be met with, if sought for in suitable localities, throughout the 

 summer, and that before the winter sets in all will have disappeared. 

 Whence have they gone ? Whither do they go ? These ques- 

 tions cannot even now be answered fully, though the study of 

 the emigration and immigration of our native birds has been 

 prosecuted with untiring zeal by generations of ornithologists. 

 Nevertheless their labours on the subject of migration have pro- 

 vided us with some very remarkable facts which, as incentives to 

 observation and the study of geography, would be hard to beat. 



The many problems raised by a study of the phenomena of 

 migration obviously cannot be analysed here, and it is proposed, 

 therefore, to do no more than sum up the essence of the facts 

 brought to light. 



Briefly, of the three hundred species of birds which are entitled 



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