CONTENTS. 



PAGE 



INTRODUCTORY. THE UTILITY OF BIRDS IN NATURE, . . . . 1 



CHAPTER I. THE VALUE OF BIRDS TO MAN, 23 



Primitive Man's Relations to Nature, .23 



Changed Relations produced by Agriculture, . . . . .24 



Man at War with Nature in the New World, . . . . . .25 



The Increase of Insect Pests, . , .-"."-. . . . .27 



The Number of Insects, . . .28 



The Reproductive Capacity of Insects, . . ...... 28 



The Voracity of Insects, . .30 



The Great Loss to American Agriculture by Insect Ravages, ... 31 

 Losses by Insect Ravages in Massachusetts, . >, . . , . .36 



The Capacity of Birds for destroying Pests, . "''-^''^ . . . . 40 



V 

 The Digestion of Birds, . . . ... 5^ . . 40 



The Growth of Young Birds, . . ... . . * ? . 42 



The Amount of Food required by Young Birds, . . . " . 44 



The Time required for Assimilation of Food, ..... 49 



The Number of Insects eaten by Young Birds in the Nest, . . 51 



The Amount of Food eaten by Adult Birds, . . . . . . 57 



Birds save Trees and Crops from Destruction, , . ', . .63 



The Increase of Injurious Insects following the Destruction of Birds, . 72 



The Destruction of Injurious Mammals by Birds, 76 



The Value of Water-birds and Shore Birds, . . . . . . 80 



The Commercial Value of Birds, 81 



The Esthetic, Sentimental, and Educational Value of Birds, . . 85 



CHAPTER II. THE UTILITY OF BIRDS IN WOODLANDS, .... 90 



The Relations of the Bird to the Tree, . ! . . . .91 



The Forest Planters, . . 92 



The Influence exerted by Birds and Squirrels on the Succession of 



Forest Trees, . . '-.'."' ^ 



The Tree Primers, 99 



The Guardians of the Trees, 100 



CHAPTER III. BIRDS AS DESTROYERS OF HAIRY CATERPILLARS AND 



PLANT LICE, ,- .111 



CHAPTER IV. THE ECONOMIC SERVICE OF BIRDS IN THE ORCHARD, . 149 



CHAPTER V. SONG BIRDS OF ORCHARD AND WOODLAND, . . . 155 



Woodland Thrushes, 155 



Kinglets, . 16 



Nuthatches and Tits, . 163 ' 



