Contents. 



PAGE 



Intkoductory. — The Utility of Birds in Nature, .... 1 



Chapter I. — The Value of Birds to Man 23 



Primitive Man's Belations to Nature 23 



Changed Belations produced by Agriculture 24 



Man at "War with Nature in the New "World 25 



The Increase of Insect Pests 27 



The Number ot 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 



The Digestion of Birds 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 7fl 



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 96 



The Tree Pruners, 99 



The Guardians of the Trees, 100 



Chapter III. — Birds as Destroyers of Hairy Caterpillars and 



Plant Lice, Ill 



Chapter IV. — The Economic Service of Birds in the Orchard, . 149 



Celapter V. — Song Birds of Orchard and Woodland, . . . 155 



Woodland Thrushes, 155 



Kinglets, 160 



Nuthatches and Tits, ... 163 



