200 THE MIGRATION OF BIRDS. 



cause, either to be lightly acquired or to be readily 

 relinquished/ The present chapter, then, meagre 

 as it is, will, I hope, serve to show that the 

 Destinations of the Migrants are of some importance 

 in a study of Avian Season Flight, and assist in no 

 small degree to its ultimate elucidation. Our 

 knowledge of the geographical distribution of 

 birds is still far from being even approximately 

 complete. Too little attention is paid to the habits 

 of birds, or to the fact of birds being migratory or 

 not, and, if the former, the dates of their arrival 

 and departure, and the various causes that initiate 

 these periodical movements. Alas ! only too often 

 has an interesting and pregnant thread of investi- 

 gation been suddenly snapped by the failure to 

 obtain such requisite information ; and until we are 

 in possession of this data I can confidently assert 

 that much will remain unsolved and inexplicable in 

 the Migration of Birds. 



1 The notoriously early age at which the Impulse to migrate 

 is manifested, seems to me one very convincing proof of the vast 

 antiquity of the habit of Migration. Young birds, as we have 

 already seen, are almost universally the first to display a restless 

 desire for Flight in autumn, and to leave their birthplace before 

 the bulk of the older individuals. 



