INTRODUCTION VH 



from contributed notes and from a few published sources. They show 

 the dates on which eggs have been actually found in various parts of 

 the country, giving the earliest and latest dates and the limits between 

 which half the dates fall, indicating the height of the season. 



The plumages are described in only enough detail to enable the 

 reader to trace the sequence of molts and plumages from birth to 

 maturity and to recognize the birds in the different stages and at the 

 different seasons. No attempt has been made to describe fully the 

 adult plumages ; this has been well done already in the many manuals 

 and State books. Partial or complete albinism is liable to occur in 

 almost any species; for this reason, and because it is practically 

 impossible to locate all such cases, it has seemed best not to attempt 

 to treat this subject at all. The names of colors, when in quotation 

 marks, are taken from Ridgway's Color Standards and Color Nomen- 

 clature (1912). In the measurements of eggs, the four extremes are 

 printed in boldface type. 



Many who have contributed material for previous volumes have 

 continued to cooperate. Receipt of material from over 500 con- 

 tributors has been acknowledged previously. In addition to these, 

 our thanks are due to the following new contributors: G. D. Alcorn, 

 Amelia S. Allen, A. E. Allin, James Bond. W. H. Carrick, C. D. Carter, 

 H. L. Cogswell, Fred Evenden, Jr., Mae Halliday, F. V. Hebard, H. 

 W. Higman, E. W. Jameson, Jr., G. F. Knowlton, H. C. Kyllingstad, 

 R. E. Lawrence, D. J. Magoon. A. H. Miller, R. F. Miller, R. H. 

 Mills, Tilford Moore, James Murdock, J. W. Musgrove, H. R. Myers, 

 L. N. Nichols, G. A. Petrides, A. L. Pickens, W. T. Shaw, W. E. 

 Shore, J. C. Tracy, H. O. Wagner, G. J. Wallace, Florence G. Weaver, 

 George Willett, and William Youngworth. 



If any contributor fails to find bis or her name in this or some pre- 

 vious volume, the author would be glad to be advised. As the demand 

 for these bulletins is much greater than the supply, the names of those 

 who have not contributed to the work during the previous 10 years 

 will be dropped from the author's mailing list. 



Photographs for this bulletin were contributed by the Museum of 

 Vetebrate Zoology, University of California, and by the University of 

 Minnesota. 



This has been, indeed, a cooperative volume. Bernard W. Tucker 

 has contributed eight complete life histories and Dr. Winsor M. 

 Tyler has written three, besides rendering valuable assistance in reading 

 and indexing a large part of the literature on North American birds. 

 Dr. Alfred O. Gross, Dr. George J. Wallace, Mrs. Florence G. Weaver, 

 Francis M. Weston, and Robert S. Woods have each contributed one 

 complete life history. 



