PLAN OF THE WORK xix 
by an ever-increasing number of enthusiastic field students, whose 
acknowledged leader for the past forty odd years has been William 
Brewster. Mr. Brewster contributed to the first edition of the ‘“Hand- 
book” data on Cambridge birds of much value; but, since that time, 
he has fortunately embodied his life studies in his ‘Birds of the Cam- 
bridge Region” (Memoir No. 4, Nutt. Orn. Club), beyond question 
the most important local work on American birds which has as yet been 
published. The data from the Cambridge region given in this edition 
of the “Handbook” are quoted, by permission, from Mr. Brewster’s 
book, where the exact limits of the area covered will be found stated. 
None of the additional records were contained in the first edition 
of the “Handbook.” Those from Ohio were supplied by Professor 
Lynds Jones, of Oberlin, long the authority on the birds of that State. 
They cover Lorain and Erie Counties. The dates, Professor Jones 
states, are ‘‘median dates of first arrival.” 
B. T. Gault, who has contributed the notes from Glen Ellyn, writes: 
“The dates given are extreme [thus contrary to the plan followed by 
other contributors], excepting in isolated cases of extra-limital species. 
My observations really cover the township of Milton, but every bird 
listed, except Gallinula galeata, Strix varia, and Aquila chrysaétos, has 
been noted within the corporate limits of the village of Glen Ellyn.” 
The records from southeastern Minnesota were supplied by Dr. 
Thomas S. Roberts, for many years the leading authority on the birds 
of Minnesota. They are based, in the main, on observations made in 
the vicinity of Minneapolis. 
Nests and Eggs.—The brief descriptions of nests and eggs are based 
on the collections of the American Museum of Natural History, supple- 
mented by the use of Baird, Brewer, and Ridgway’s ‘‘History of North 
American Birds,” Davie’s ‘(Nests and Eggs of North American Birds,” 
Ridgway’s “Manual,” and Bendire’s “Life Histories of North American 
Birds.” In describing the eggs, the color chart was used when possible; 
but it was designed with particular reference to the plumages of our 
birds, and is of less assistance in describing their eggs. The measure- 
ments of eggs are mostly from series of measurements made by Mr. H. 
B. Bailey, accompanying the Bailey collection in the American Museum, 
supplemented by reference to the works mentioned above. 
Nesting Dates.—The dates following the descriptions of nest and eggs 
are designed to indicate when the nesting season of the species in ques- 
tion begins at various localities. They are the earliest dates I have found 
for the taking of full sets of (presumably) fresh eggs of the first laying. 
These records were compiled chiefly from the data accompanying the 
collections of the United States National Museum (to which I have 
kindly been given access by Dr. C. W. Richmond), those of the Ameri- 
can Museum of National History, and the collection of Mr. J. P. 
Norris, Jr., to whom I gratefully express my indebtedness. The “Cam- 
bridge” records are all extracted, by permission, from Brewster’s 
“Birds of the Cambridge Region,” while for those from “SE. Minn.”’ 
