vi PREFACE. 



bearing on Migration has been recorded, and an 

 equally large amount of observations has been 

 made on this grand Avian Movement, but hitherto, 

 so far as T am aware, no naturalist has endeavoured 

 to grapple with the entire Phenomenon, or to record 

 the result of its general study in book form, I 

 am well aware of Pal men's endeavours, of Gatke's 

 efforts, but both these distinguished naturalists 

 have only dwelt upon a portion of the subject. I 

 am equally cognizant of the researches of Weisse- 

 mann, Harvie-Brcwn, Cordeaux, Seebohm, Coues, 

 and Allen, and a host of others ; yet none have 

 sought to exhaust the subject, even superficially, 

 or to bring our present knowledge of Migration 

 wathin the limits of order, or to reduce it to Law. 



In the present volume I have made an attempt 

 to do this. It em.bodies the results of twelve years 

 of diligent general study and research, and of at 

 least two years' close application and thought, and 

 wall, I earnestly hope, serve at least the humble 

 purpose of paving the way towards a more important 

 record. The deep interest attached to the important 

 function of Avian Hibernation has, I hope, been 

 revived. It would have been an easy matter to 

 have doubled the size of the present work had I 



