VI INTRODUCTION. 
sufficient detail to indicate the usual movements of each species;g 
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 earliest 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Although preference has been given to original unpublished mate- 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 sympathetic 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 ang 
