CONTENTS 



INTRODUCTORY REMARKS. 



THE BALANCE OF NATURE. 



RESCUE OF CROPS, FOLIAGE AND FORESTS BY BIRDS. 



QUANTITIES OF FOOD REQUIRED BY BIRDS. 



METHODS OF INVESTIGATION. 



NECESSSITY OF BIRD PROTECTION. 



SYSTEMATIC DISCUSSION. 



THE LITERATURE OF ECONOMIC ORNITHOLOGY. 



BIBLIOGRAPHY. 



