VI INTRODUCTION. 



sufficient detail to indicate the usual movements of each species; 

 it is obviously impossible to give, in a general work of such large 

 scope, all records of occurrence and all dates and no pretense at 

 perfection in this direction is claimed. Many published records, im- 

 possible to either verify or disprove, have been accepted if they are 

 apparently within the known limits of ranges. 



The nesting dates are the condensed results of a mass of records 

 accumulated from the data in over 60 of the largest egg collections 

 in the country, as well as from contributed field notes and from 

 many published sources. They indicate the dates on which eggs 

 have been actually found in one or more portions of the breeding 

 range of the species, showing the earlier and latest dates and the 

 limits between which at least half of the dates fall. The names of 

 colors, when in quotation marks, are taken from Ridgway's Color 

 Standards and Nomenclature (1912 edition) and the terms used to 

 designate the shapes of eggs, when in quotation marks, are taken 

 from Ridgway's Nomenclature of Colors (1886 edition). The heavy- 

 faced type in the measurements of eggs indicate the four extremes of 

 measurement. 



After a few introductory remarks where these seem desirable, the 

 life history of each species is written in substantially the following 

 sequence: Spring migration, courtship, nesting habits, eggs, young, 

 sequence of plumages to maturity, seasonal molts, feeding habits, 

 flight, swimming and diving habits, vocal powers, behavior, ene- 

 mies, fall migration, and winter habits. An attempt has been made 

 to avoid repetition in dealing with subspecies. 



Although preference has been given to original unpublished mate- 

 rial, so little of this has been received that it has seemed best to 

 quote freely from published material whenever the life history could 

 be improved by so doing. The author does not guarantee the correct- 

 ness of any statements quoted, but has selected only such as seem to be 

 reliable. Quotations from or references to published matter are in- 

 dicated by a date in parentheses after the author's name and the 

 reference may be found by turning to the bibliographical index at 

 the end of each part. 



Acknowledgments are due to many who have helped to make the 

 work a success, by contributions and by sjnnpathetic encourage- 

 ment. Dr. Louis B. Bishop has contributed many hours of careful 

 work in collecting from published material and other sources a mass 

 of data needed for the distributional part of this work and has 

 helped to tabulate and arrange it. He has also been very helpful to 

 the author in his studies of plumages and has helped and encouraged 

 him in many ways. Dr. Charles W. Townsend has furnished a lot 

 of original contributions, has read over and corrected much of the 

 manuscript and has written the entire life histories of the puffin and 



