18 BIRDS IN THEIR RELATIONS, TO MAN. 



part of which the present chapter is necessarily a poor parallel, 

 —this work of Wilson's laid the true foundation of ornithology 

 in the United States. And it contained many references to 

 the purely economic phases of bird life, showing again and 

 again the value of different species as destroyers of insects. 

 Before the century had run its first quarter the great Audubon 

 was exploring the wilderness in all directions, making wonder- 

 ful paintings of its bird inhabitants and drawing up excellent 

 accounts of their ways and habits. The publication of his 

 work began in 1827 and continued till 1839. He also made 

 many references to feeding habits and economic values, as 

 did Nuttall, whose volumes, published from 1832 to 1834, 

 were largely based on the works of these two earlier naturalists. 

 From 1850 onward the technical science of ornithology 

 made wonderful strides, which it is no part of our present 

 purpose to describe. But about this date various persons 

 interested in agriculture began to see the value of birds as 

 insect destroyers, realizing that the unchecked destruction of 

 these feathered allies was leading to an alarming increase 

 of insect pests. The agricultural journals and the reports of 

 agricultural and horticultural societies began to publish many 

 excellent articles, which showed careful observations and 

 thoughtful consideration of the relation of birds to crop pro- 

 duction. The titles of most of these papers will be found 

 in the bibliography at the end of this book, so that there is 

 no need for specific mention here. One by Wilson Flagg, 

 however, published in the Report on the Agriculture of 

 Massachusetts for 1861, is so remarkable that we cannot pass 

 it by. It is entitled " The Utility of Birds," and is a general 

 survey of the field which would do honor to a man to-day, 

 after all the intervening years of study and discovery. It is 

 based on the thesis distinctly stated in these words, which are 

 italicized in the original article, — that each species of bird per- 

 forms certain services ' in the economy of nature, which cannot be 

 so well accomplished by any other species. This paper was 



