VI PREFACE. 



(Woodhewers) ; the Macrochires, containing the Trochilidse (Hum- 

 ming Birds) and Mcropodidse (Swifts), and the Heterodactylse, repre- 

 sented only by the TrogonidEe (Trogons). 



Part VI (the present volume) contains the Picarise, comprising the 

 families Picidse (Woodpeckers), Capitonidse (Barbets), Kamphastidse 

 (Toupans), Bucconidse (Puff Birds), and Galbulidse (Jacamare); the 

 Anisodactylse, with families AlcedinidsB (Kingfishers), Todidae 

 (Todies), and Momotidse (Motmots) ; the Nycticoracise, with families 

 CaprimulgidsB (Goatsuckers) and Nyctibiidse (Potoos), and the 

 Striges, consisting of families Tytonidse (Bam Owls) and Bubonidae 

 (Eared Owls)> 



In these six volumes are treated, in detail (that is, with full synony- 

 mies and descriptions), besides the Families above mentioned and 

 the higher groups to which they, respectively, belong, 520 genera, 

 2111 species and subspecies, besides 155 extralimital genera and 478 

 extralimital species and subspecies whose diagnostic characters are 

 given in the "keys", and their principal synonymy (full synonymy 

 in case of the genera) given ia footnotes. 



Acknowledgments are due to the same individuals and institu- 

 tions as those mentioned in previous volumes for the loan of speci- 

 mens needed in the preparation of the present one; also to Dr. 

 Jonathan Dwight, jr., of New York City; Dr. L. C. Sanford, of New 

 Haven, Connecticut; Mr. Harry S. Swarlh, of Los Angeles, California; 

 Mr. A. B. Howell, of Covina, California, and the Museum of Verte- 

 brate Zoology (University of California), the latter through Mr. 

 Joseph Grinnell, Director. 



To Dr. Charles W. Richmond, Acting Curator of the Division of 

 Birds, U. S. National Museum, the author is indebted for the privilege 

 of free access to his unique and extremely valuable card-catalogue 

 collection of references to the first publication of generic, specific, and 

 subspecific names, ior information concerning puzzling questions of 

 nomenclature, and invaluable help in reading proof sheets; and to 

 Mr. J. H. Riley, Aid in the Division of Birds, for assistance in various 

 ways, especially the measuring of several thousands of specimens. 



The original drawings of the outline figures illustrating generic 

 details (Pis. I-XXXVI), except those previously published, were 

 made by Miss Ruth G. CoUette, of Washington, D. C. 



Robert Ridgwat. 

 Febbuakt 4, 1914. 



