PREFACE. 



The year covered by our fourth volume has been marked 

 by a steady advance rather than by any very striking 

 event in British ornithology. 



The interest in the Marking 8cheme continues to grow, 

 and the recoveries already announced show excellent 

 promise for the future. Such an inquiry must necessarily 

 be continued for some years before results of real value 

 can be obtained, but we now feel assured that the ringing 

 of birds, if conducted on a scale equal to that of last year, 

 will be the means of our gaining a considerable knowledge 

 of the exact movements of individual birds — a subject 

 of which we now know practically nothing. We may 

 here again express our gratitude to those numerous 

 readers who, by their enthusiastic co-operation, are 

 making the scheme a success. 



The Crossbill irruption and the resultant nesting 

 have again engaged the careful attention of many con- 

 tributors, and never before has such a visitation been so 

 well and thoroughly recorded. 



The value of a careful study of geographical races is 

 becoming more widely recognized, and the knowledge 

 gained by this means of the origin of a number of 

 immigrants, as in the case of Jays, Great Tits, and 

 Woodpeckers recorded in the pages of this volume, 

 must surely convince the most sceptical that the sub- 

 division of species into racial forms is of real practical 

 value to the student of migration, apart from its 

 undoubted interest to the evolutionist. 



Notes on various interesting points connected with the 

 life-history and distribution of our birds have again shoM^n 

 a growth both in number and importance, and we hope 

 that this valuable feature will continue to increase. 



