ECONOMIC VALUK OF BIRDS. 9 



we do not realize that Gulls aiul some other water hirds 

 are also benelicial as scavengers in eating refuse which, 

 if left floating on the water, would often be cast ashore 

 to decay. Dr. George F. Ganmer, of Yucatan, tells me 

 that the killing of immense nnmbers of Herons and other 

 littoral birds in Yucatan has been followed by an increase 

 in human mortality among the inhabitants of the coast, 

 which he is assured is a direct result of the destruction of 

 birds that formerly assisted in keeping the beaches and 

 bayous free from decaying animal matter. 



Lack of space forbids an adequate treatment of this 

 subject, but reference to the works and papers mentioned 

 below* will support the statement that, if we were de- 

 prived of the services of birds, the earth would soon 

 become uninhabitable. 



Nevertheless, the feathered protectors of our farms 

 and gardens, plains and forests, require so little encour- 

 agement from us — indeed, ask only tolerance — that we 

 accept their services much as we do the air we breathe. 

 We may be in debt to them past reckoning, and still be 

 unaware of their existence. 



But to appreciate the beauty of form and plumage of 



* Notes on the Nature of the Food of the Birds of Nebraska, by 

 S. Aughey; First Annual Report of the United States Entomological 

 Commission for the Year 1877, Appendix ii, pp. 13-G2. The Food of 

 Birds, by S. A. Forbes ; Bulletin No. 3, Illinois State Laboratory of 

 Natural History, 1880, pp. 80-148. The Regulative Action of Birds 

 upon Insect Oscillations, by S. A. Forbes, ibid.. Bulletin No. 6, 18S3, 

 pp. 3-32. Economic Relations of Wisconsin Birds, by F. II. King; 

 Wisconsin Geological Survey, vol. i, 1882, pp. 441-GlO. Report on the 

 Birds of Pennsylvania, with Special Reference to the Food Habits, 

 based on over Four Thousand Stomach Examinations, by B, 11. War- 

 ren ; Ilarrisburg, E. K. Meyers, State Printer, large 8vo, pji. 434. plates 

 100. The English Sparrow in North America, especially in its Rela- 

 tion to Agriculture, prepared under the Direction of C. Hart Merriam, 

 by Walter B. Barrows; Bulletin No. 1, Division of Economic Orni- 

 thology and Mammalogy of the United States Department of Agricul- 



