10 MIGRATION OF BIRDS. 



skylark of the summer, overflowing with happiness and 

 complacency, and half bursting with song ! 



The RING OUSEL is another bird of passage that visits 

 us with the greatest regularity in spring and autumn ; but 

 our winter is too cold for him, I suppose, for he never stays 

 above three weeks in autumn, then passing southwards 

 towards the Sussex coast : in the spring his stay is still 

 shorter, as he is then in a hurry to get to his home among 

 the hills of the north, where he nestles. Hindhead is the 

 resting-place of the ring ousel on both his passages, and 

 he keeps about the tops of the hills. Stragglers have been 

 shot at Rodborough and on Highdown's Ball, but this is a 

 rare occurrence. 



The migration of birds is a study in which our ornitho- 

 logists have not yet made any great progress. White and 

 Bewick have touched on it, but not quite satisfactorily ; 

 they point to migration as a kind of a tree of knowledge, 

 whose produce, as that of the old one, is forbidden fruit. 

 Now migration is the simplest thing in the world. At cer- 

 tain periods of the year the proper food of certain species 

 of birds fails in the native countries of those species ; this 

 is the ' cause ' of migration : then the first 'law' of migration 

 is the ' instinctive and perhaps in some instances experi- 

 mental knowledge that proper food is about to fail.' The 

 next important facts are, that the great mass of birds of 

 passage are insect-eaters, and secondly, that insects, at the 

 approach of winter, disappear first from the most north- 

 erly countries : if water-birds or waders, still the facts 

 obtain ; the freezing of lakes, rivers and mud-banks first 

 occurs in the higher latitudes : hence the second law, that 

 ' migration is in a southward direction.' Thus, migration 

 begins in autumn and goes on till winter, keeping pace 



