INTRODUCTION 



This is the seventh in a series of bulletins of the United States 

 National Museum on the life histories of North American birds. 

 Previous numbers have been issued as follows : 



107. Life Histories of North American Diving Birds, August 1, 

 1919. 



113. Life Histories of North American Gulls and Terns, August 

 27, 1921. 



121. Life Histories of North American Petrels, Pelicans and their 

 Allies, October 19, 1922. 



126. Life Histories of North American Wild Fowl, May 25, 1923. 



130. Life Histories of North American Wild Fowl, June 27, 1925. 



135. Life Histories of North American Marsh Birds, "1926." 

 (-March 11, 1927). 



The same general plan has been followed, as explained in previous 

 bulletins, and the same sources of information have been utilized. 



The classification and nomenclature adopted by the American 

 Ornithologists' Union, in its latest check list and its supplements, 

 have been followed, mainly, with such few changes as, in the author's 

 opinion, will be, or should be, made to bring the work up to date, 

 and in line with recent advances in the science. 



The main ranges are as accurately outlined as limited space will 

 permit; the normal migrations are given in sufficient detail to indi- 

 cate the usual movements of the species; no attempt has been made 

 to give all records, for economy in space, and no pretense at com- 

 plete perfection is claimed. Mam^ published records, often repeated, 

 have been investigated and discarded; many apparently doubtful 

 records have been verified; some published records, impossible to 

 either verify or disprove, have been accepted if the evidence seemed 

 to warrant it. 



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

 taken from the data in a large number of the best egg collections 

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

 few published sources. They indicate the dates on which eggs have 

 been actually found in various parts of the country, showing the 

 earliest and latest dates and the limits between which half the dates 

 fall, the height of the season. 



The plumages are described only in enough detail to enable the 

 reader to trace the sequence of molts and plumages from birth to 



