VIII INTRODUCTION 



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

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

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

 uals. The names of colors, when in quotation marks, are taken 

 from Ridgway's Color Standards and Nomenclature (1912) and the 

 terms used to describe the shapes of eggs are taken from his Nomen- 

 clature of Colors (1886 edition). The heavy-faced type in the 

 measurements of eggs indicates the four extremes of measurements. 



Many of those who contributed material for former volumes have 

 rendered a similar service in this case. In addition to those whose 

 contributions have been acknowledged previously, our thanks are 

 due to the following new contributors: Photographs, notes, or data 

 have been contributed by W. B. Alexander, Clark Blickensderfer, 

 C. E. Chapman, Karl Christofferson, C. W. Colthrup, Walter Colvin, 

 W. M. Congreve, Joseph Dixon, J. G. Gordon, S. A. Grimes, W. C. 

 Herman, Frank Howland, W. I. Lyon, T. R. Miley, D. J. Nicholson, 

 K. H. Rauch, Russell Richardson, jr., W. A. Smith, J. D. Soper, 

 E. S. Thomas, M. B. Trautman, C. F. Walker, F. M. Weston, H. F. 

 Witherby, A. H. Wood, jr., and C. J. Young. 



Receipt of material from over 250 contributors has been acknowl- 

 edged in previous volumes. 



Through the courtesy of the Biological Survey, the services of 

 Frederick C. Lincoln were secured to compile the distribution para- 

 graphs. With the matchless reference files of the Biological Survey 

 at his disposal and with some advice and help from Dr. Harry C. 

 Oberholser, his many hours of careful and thorough work have 

 produced results far more satisfactory than could have been attained 

 by the author, who claims no credit and assumes no responsibility 

 for this part of the work. The few minor changes made in the 

 system do not materially alter the general plan. 



Dr. Charles W. Townsend has written the life histories of two 

 species and the Rev. Francis C. R. Jourdain, a well-known British 

 authority, has contributed the life histories and the distributions of 

 six Old World species, which are known to us only as rare stragglers. 

 Mr. J. H. Riley has furnished descriptions and measurements of 

 some rare eggs in the National Museum. We are indebted to Mr. 

 H. F. Witherby for the loan of the valuable photographs of the 

 knot, taken by Admiral Peary, which the author publishes at his 

 own risk, without permission. 



As most of the shore birds are known to us mainly, or entirely, as 

 migrants it has seemed desirable to describe their migrations quite 

 fully. As it is a well-known fact that many, if not all, immature 

 and nonbreeding shore birds remain far south of their breeding 

 ranges all summer it has not seemed necessary to mention this in 



