INTRODUCTION. The monumental work undertaken and so ably begun by Maj. Charles E. Bendire has remained unfinished, and no additional volumes have been published since his death. In 1910 the author undertook to continue the work and began to gather material for it with the cooperation of American ornithologists. The following well-known ornithologists offered to help in gathering material from their several sections of the country: Harold H. Bailey, Walter B. Barrows, Allan Brooks, Earle A. Brooks, William L. Finley, Benjamin T. Gault, A Brazier Howell, Lynds Jones, Elmer T. Judd, Charles E. Keyes, Arthur H. Norton, Putnam B. Pea- body, T. Gilbert Pearson, Charles J. Pennock, Walter W. Perrett, Samuel F. Rathbun, Thomas S. Roberts, Aretas A. Saunders, Wil- liam E. Saunders, Witmer Stone, Myron H. Swenk, Charles W. Townsend, Edward E. Warren, and Arthur T. Wayne. The Biological Survey of the Department of Agriculture, at Washington, very kindly placed at my disposal its matchless bibliographical index to published material on North American birds, and a mass of references were carefully copied by Mr. Edward A. Preble. With this and the author's private index as guides nearly every publication of importance relating to North American birds has been consulted. While the scope of the work was originally intended to cover substantially the same ground covered by Maj. Bendire's work and in practically the same manner, it has since seemed best to somewhat enlarge its scope and to cover more ground, with the different phases of the life histories arranged in a more definite and uniform sequence, so that the reader may more readily find the parts in which he is interested. The classification and nomenclature adopted by the American Ornithologists' Union in its Check List have been strictly followed, regardless, of the author's views on the status of certain species and subspecies; as this is not a work on systematic ornithology, it has seemed best to merely refer to these views briefly in the text and not attempt to discuss them fully. The main breeding and winter ranges are as accurately outlined as limited space will permit; the normal migrations are given in
