INTRODUCTION. Ix 
tional part of the work was practically all done by him, with what 
assistance Doctor Bishop and the author could give him. No one 
who has not done work of this kind can appreciate the mass of detail 
to be handled and the expert knowledge necessary to handle it 
properly. 
Finally, thanks are due to the author’s devoted wife, Madeleine 
V. Bent, for many weary hours of painstaking work in typewriting, 
reading, and correcting manuscript and in proof reading. 
No one is so well aware of the many shortcomings and omissions 
in this work as the author. Allowance must be made for the magni- 
tude of the undertaking. If the reader fails to find mentioned in 
these pages some things which he knows about the birds, he can blame 
himself for not having sent them to 
Tue AUTHOR. 
