18 INTRODUCTION. 



As this bulletin is intended to be of practical benefit to the farmer 

 descriptions are given of all our birds of prey by which he may tell his 

 friends from his foes, that he may preserve the former and destroy the 

 latter. These descriptions have been made as short and as terse as is 

 compatible with clearness and have been stripped of all technicalities. 

 Some little explanation is needed in reference to measurements : Length 

 means the total length of fresh specimens from end of bill to tip of tail. 

 Extent is also taken from fresh specimens and is measured from the 

 tip of one wing to that of the other, they being moderately stretched. 

 The wing measurement may be from a dried skin and is taken from the 

 bend of the wing to the end of the longest feather. The Tail measure- 

 ment is taken from the tip of the longest feathers to the back part of 

 the eminence of the oil sac. Moreover, to insure the correct iden- 

 tification of the several species, figures of the more important have 

 been added. By means of the descriptions and figures it is believed 

 that the farmer may readily become acquainted with the birds here 

 treated of. For the benefit of those whose interest in the subject ex- 

 tends beyond its economic side, a short account of each species is added, 

 with some particulars of their nesting habits, etc. The nomenclature 

 adopted is that of the American Ornithologists' Union. The geo- 

 graphical races, or subspecies, are included under the typical species, 

 since the habits of both are practically identical, the main differences 

 between them being color and to a less extent size. 



In closing, the writer wishes specially to express his indebtedness to 

 Mr. H. W. Henshaw, who has assisted him in various ways in the prep- 

 aration of the present bulletin. He also wishes to acknowledge his 

 obligations to Dr. E. A. Mearns, U. S. Army, who kindly placed in his 

 hands original data on the food of several hundred hawks and owls. 



To Dr. W. 0. Avery, F. E. L. Beal, C. S. Brimley, Amos W. Butler, 

 Charles Dury, E. Elliott, L. S. Foster, Gustave Kohn, Austin F. Park, 

 William Praeger, F. Stephens, and Dr. B. H. Warren, who have fur- 

 nished manuscript data on the food of rapacious birds, thanks are also 

 due. 



A large majority of the stomachs which furnish data for the tables 

 accompanying this bulletin and lend them their chief value were pre- 

 sented by the following persons, to whom the writer wishes to extend 

 his sincere acknowledgments : 



Ezra Acker. Capt. Charles Bendire. 



Howard Acker. H. C. Bennett. 



Dr. G. S. Agersborg. 0. E. Beyer. 



R. C. Alexander. R. H. Blain. 



C. K. Averill. C. S. Brimley. 



Dr. W. C. Avery. H. Broughton, jr. 



Vernon Bailey. E. L. Brown. 



A. Baker. Herbert Brown. 



W. B. Barrows. William Brown. 



A. R. Bellwood, F. L. Burns. 



