PREFACE. Vii. 



in the later editions of his work as well as by quite the majority 

 of writers to the present day. Of the enormous mass of ornith- 

 ological literature issued since YarrelPs day, I have a vailed myself 

 by gleaning where anything may be gleaned for my purpose, 

 and if any of the works thus consulted are not included in the 

 Bibliography it is because I have felt it necessary to restrict 

 the list to the principal and most interesting. 



In conclusion I have to thank a number of past and present 

 correspondents and friends who have obliged me with names 

 or information for this book, and to beg their indulgence for 

 not detailing more specifically the help they have given me. 

 I must also add a word of thanks to Mr. H. F. Witherby for 

 his kindly suggestions, and the interest he has shown in the 

 publication of the work. 



H. KIRKE SWANN. 



38, Great Queen Street, Kingsway, 

 London, W.C., 



December I2tk, 1912. 



