PREFATORY NOTE xi 



but they have gone out as chapters in forbid- 

 ding public documents, or else separately in 

 loose pamphlets which in most cases have been 

 speedily lost. It is impracticable for the or- 

 dinary man to get copies of them now if he 

 tries, and their usefulness has therefore come 

 to an untimely end. Among them are original 

 and valuable essays by Dr. C. Hart Merriam, 

 Chief of the Biological Survey until his resig- 

 nation in 1910, when H. W. Henshaw succeeded 

 to his office; Vernon Bailey, the assistant in 

 charge of field investigations ; David E. Lantz, 

 Wilfred H. Osgood, E. W. Palmer, Stanley E, 

 Piper, E. "W. Nelson, Edward A. Goldman, and 

 others attached to the Department. 



Knowing the accuracy and importance of this 

 half-lost material, and also aware that nothing 

 better could be furnished in its stead, I have 

 not hesitated to make liberal use of it, often 

 in its own well-chosen language. It was writ- 

 ten for the benefit of the public ; and I am con- 

 fident the gentlemen above mentioned will 

 gladly see it renew its usefulness in the per- 

 manent form a bound book affords, and rejoice 

 in the greater force their facts and recommen- 



