CIRCULAR No. 363 OCTOBER 1935 
UNITED STATES DEPARTMENT OF AGRICULTURE 
WASHINGTON, D.C. 
THE MIGRATION OF NORTH AMERICAN BIRDS’ 
By Freperick C. LINcoLn, senior biologist, in charge Section of Distribution and 
Migration of Birds, Division of Wildlife Research, Bureau of Biological Survey 
CONTENTS 
Page | Page 
Introduction-.-------- eed et ee 1 | Routes of migration—Continued. 
IViVStenyOlmmicratloneeese ee aren nase 3 Mackenzie Valley-Great Lakes-Mississippi 
EUISTORICAACCOUNTS== a= eee oe ee 3 Valley route and tributaries______________ 45 
Advantages of eA GEA eee a ee 4 RAC CCOBSTLOULC mee ae ee 47 
Theories of causes of migration ______------ 5 Pacificioceani@¢route = 2- ss ee 49 
When bindsnmicraees= aes oe) ae eee Uf ATC UT CMOULGCS reese ee ee a ea ee 52 
Movements of species and groups_____----- 8 | Evolution of migration routes______-_-_-____ 52 
Nocturnal and diurnal migration___-_-_--__ IE Warn neAn l rooney = es Se 55 
Owe DILdSsmi erate tee ee ae 13) AW Verein, maa R AO M2 ee 55 
Speed of flight and speed of migration___--_- 13 | Perils of migration aS Rete pe eee sit Ss SE ee 56 
Altitudes at which birds travel ____--------- 22 SCOMITIS Syepe goes ees oe ee en ae ope 56 
Orientation = ees ee th eee ee 23 NCH ANVODStEUCHIONSt = 252 =n eee eee 57 
Segregation during migration______-_-------- 2 yar a RNAUIS bi OMe se eng os ee eR ee es 59 
Wiherebinrdsmicratcee see a ee ee ene 27 | Influence of the weather on migration_______- 59 
Distances of migration vary .______-------- Zila erObleMSORmisTatlon aps sess ee ee 61 
Short and undetermined migration _____ Eee Ziel Ban Gin sesh diese. ee eee ne eee ee 61 
Variable migrations within species_________ 28 Movements of residents___________________ 62 
Fall flights not far south of breeding ranges_ 29 Migration of the white-throatedsparrow. _- 63 
Long-distance migrations_________-_---___- 30 Migration ofthe yellow-billedloon____-___- 63 
Routesotmicratione ese ee eee ee 33h GC onclisions&24 3 3 be eee a ee eee 65 
Wideand narrow migration lanes_ --___ ie OA 348|(e Bibliosrap Dy aos = ee eee = eee 66 
AtlanticoceaniGroutereesas) = ese Olas Md exsssseoes SCE EY Se ae eee ee 69 
Atlantic coast route and tributaries______-_- AQ | 
INTRODUCTION 
Where do the birds go each fall that have nested in our dooryards 
and frequented the neighboring woods, hills, and marshes? Will the 
same ones return again to their former haunts next spring? What 
dangers do they face on their round-trip flight and in their winter 
homes? These and other questions on the migratory habits of birds 
puzzle the minds of many who are interested in the feathered species, 
whether it be the farmer who profits by their tireless warfare against 
the weed and insect pests of his crops, the bird student who enjoys an 
abundance and variety of feathered inhabitants about him, or the 
hunter who wants a continuation from year to year of the sport of 
wild-fowling. Lack of information on the subject may mean the loss 
of an important resource by unconsciously letting it slip from us. 
Ignorance of the facts may be responsible for inadequate legal protec- 
tion for such species as may urgently need it. More general knowl- 
edge on the subject will aid in the perpetuation of the various migra nts, 
the seasonal habitats of some of which are in grave danger from man’s 
1 This circular supersedes Department Bulletin 185, Bird Migration, by Wells W. Cooke, published in 
1915. Inaddition to his own original investigations in the field and those reflected in the files of the Biologi- 
cal Survey, the author has made free use of the writings of Professor Cooke, Alexander Wetmore, William 
Rowan, A. Landsborough Thomson, H. A. Allard, and others. To all these grateful acknowledgment is 
made, particularly to Doctor Wetmore, Assistant Secretary of the Smithsonian Institution, who has read 
the entire manuscript and made many valuable comments and suggestions. 
134984°—35——1 1 
