CONTENTS

Page
Introduction 1
Mystery of migration 3
  Historical accounts 3
Advantages of migration 4
Theories of causes of migration 5
When birds migrate 7
Movements of species and groups 8
Nocturnal and diurnal migration 11
How birds migrate 13
Speed of flight and speed of migration 13
Altitudes at which birds travel 22
Orientation 23
Segregation during migration 25
Where birds migrate 27
Distances of migration vary 27
Short and undetermined migration 27
Variable migrations within species 28
Fall flights not far south of breeding ranges 29
Long-distance migrations 30
Routes of migration 33
Wide and narrow migration lanes 34
Atlantic oceanic route 39
Atlantic coast route and tributaries 42
Mackenzie Valley-Great Lakes-Mississippi Valley
    route and tributaries
45
Pacific coast route 47
Pacific oceanic route 49
Arctic routes 52
Evolution of migration routes 52
Vertical migration 55
Vagrant migration 55
Perils of migration 56
Storms 56
Aerial obstructions 57
Exhaustion 59
Influence of the weather on migration 59
Problems of migration 61
Banding studies 61
Movements of residents 62
Migration of the white-throated sparrow 63
Migration of the yellow-billed loon 63
Conclusions 65
Bibliography 66
Index 69