CONTENTS 



PAGE 



INTRODUCTION ..... i 



PART I 

 THE BIOLOGY OF SPRING 



IMPRESSIONIST SKETCH . . . . -19 



YOUNG THINGS. ... . . 26 



THE TALE OF TADPOLES . . . -32 

 THE EEL-FARE ... ... 41 



CATERPILLARS . . ... 51 



RHYTHMS IN PLANT LIFE . . . .60 



THE RETURN OF THE BIRDS . 68 



SOME QUESTIONS CONCERNING MIGRATION . . -76 



RE-AWAKENINGS . . . . . .86 



SPRING FLOWERS . . . . . .92 



PART II 

 THE BIOLOGY OF SUMMER 



IMPRESSIONIST SKETCH " ." . . . -103 



SUMMER FLOWERS . ' . . . .112 



SUMMER INDUSTRIES . . . . > . -123 



COURTSHIP OF BIRDS . . . . . 135 



THE SONG OF BIRDS . . . . .148 



THE NATURAL HISTORY OF NESTS . . . 157 



BIRDS' EGGS . . . . . . . 170 



WITHIN THE EGG . . * , . . 179 



LEARNING TO LIVE . . . * . . 186 

 THE PLASTICITY OF LIFE ..... 197 



ADOLESCENCE . . . . . . .211 



vii 



