The Migration of Birds

CONTENTS

CHAP.		PAGE
I.	Migration of Birds	1
	Definition—Variation of migration.
II.	Cause and Origin of Migration	13
	Direction of passage—The potentiality of flight—Habit of wandering—Memory—Extension of range—Influence of Temperature—Desire for Light—Glacial Epoch—Food Basis—Sexual Impulses—Competition.
III.	Routes	33
	Route or Broad Front—Coasting—Fly-lines—Isepipteses—Land-bridges—Coast Lights.
IV.	The Height and Speed of Migration Flight	47
	Altitude of Normal Migration—Variation in Speed—Effect of Wind.
V.	Orientation and Route Finding	56
	Route Finding—Use of Memory—Eyesight—Errors—Guidance of Young—Beam Winds—Homing of Terns.
VI.	The Distances Travelled by Birds	65
	The Swallow—Variation in Distances—Marking Birds—Results—Routes of the Golden Plover—Evolution of the Routes.

VII.	Migration and Weather	83
	Knowledge of Approaching Weather—Favourable and Unfavourable Conditions—Importance of Winds—Cyclonic and Anticyclonic Winds—Continental Migration.
VIII.	The Perils of Migration	104
	Contrary Winds—Lighthouses and Lightships—Leeward Drift—Catastrophes.
IX.	Early Ideas of Migration	114
	Literature—Hibernation—Carriage of Small by Large Birds.
X.	Suggestions and Guesses	119
	Trans-Atlantic Migration—Ship-borne Wanderers—Storm-blown Birds—Casual Wanderers—Swimming and Walking.
XI.	Summary	126
	Bibliography	131
	Index	135

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