As human interest in birds spread, there has arisen considerable feeling against the killing of small birds for food or game. It was realized that insectivorous birds were of benefit to man through their assistance in keeping down the abundance of insects injurious to agriculture, to which was coupled the aesthetic appeal of birds in general, through their beauty of form, colour and note, to the sympathetic and understanding mind. Use of the feathers of birds in decorative dress has been the custom from remote times, a custom that at the close of the last century culminated in a fashion that required the placing of stuffed skins or parts of skins of birds in more or less grotesque attitudes upon women's hats.
The resultant demand for feathers led to the destruction of birds by the hundred thousand. Plume-hunting became a lucrative business, and led to search for strange and beautiful feathers throughout the world. Terns, gulls, herons, birds of paradise, hummingbirds, to say nothing of countless familiar song-birds, were slaughtered to supply an unthinking and somewhat senseless desire for decoration, a course that led to great diminution in numbers in many species of birds. The destruction wrought was especially rapid in species that breed in colonies. Herons, terns and grebes, brought together by the paramount instinct for repro duction, were held by their eggs or young to a limited area, and so were easy to kill in large numbers. As this killing entailed the loss of eggs and the starvation of young, these species suffered to such an extent that some almost disappeared as living forms. As understanding of the results of such brutal methods arose, there resulted a revulsion against this fashion which led to the formation of such bird-protective organizations as the Audubon Society that have brought forcibly to public attention the evils of plume hunting. This has resulted in a partial change in fashion, and in legislation against plume importation and traffic. It is now gen erally recognized in England and the United States that bird protection is meritorious, a sentiment spreading rapidly to other countries so that international conventions have been held to pro mote it.
In connection with protective measures it is realized that the Caucasian race in its present civilization has modified natural environments to such an extent that many avian inhabitants of our earth are being crowded out of existence. To procure the continuance of interesting forms, some for their economic worth and some for their aesthetic interest, reservations or sanctuaries have been formed which birds may frequent without molestation. In Europe such preserves were made primarily to protect upland game birds, and are thrown open to hunting at the proper season. In the United States reservations have been established to cover areas where herons, terns, or similar birds nest and consist of low coastal islands, or swamp and marsh lands of little monetary value. Both types of sanctuary are now found in many countries.
The result of such protection, enforced in most instances by paid wardens, has been to increase the numbers of many birds. The egret and snowy heron, at one time reduced from a vast multitude whose breeding colonies were so populous that, from a distance, they appeared like vast white blankets, to a condition where it was unusual to see a single individual, have become again common in extensive areas. Terns have returned to colonies that were deserted for years, and the pelican maintains its numbers in spite of much unthinking persecution.
In the United States there are at the present time 76 bird reservations under jurisdiction of the Department of Agriculture, ranging in size from a few acres to several hundred square miles, while light-house reservations, national parks, and similar tracts under supervision of other governmental departments have also been designated as bird preserves. In addition, various States are now developing the idea of game sanctuaries which are also refuges for birds. Pennsylvania, at the present time, has 88 sanc tuaries of this kind, including nearly 73,00o acres. Private sanc tuaries also are multiplying and afford much protection ; many have been established as local enterprises by cities, towns, or by groups of private individuals.
Economic Studies.—Early information on the economic value of birds was based largely on field observation of living birds and many of the data obtained were erroneous. The method should be checked by the stomach examination, as developed largely by the Bureau of Biological Survey, of the U.S. Department of Agriculture. In this a series of stomachs of any given species of bird is secured, so far as practicable, at intervals throughout the year, under as many varying conditions of life as possible. These contents are examined under a microscope with low magni fication, and the different kinds of insects, seeds, bones or other materials sorted. There is thus afforded a picture of the actual food preferences of the species concerned and the status of the bird is decided on this basis as useful or harmful. These data have been of great use in arranging protection for species that assist in the war on insects injurious to crops, or that are proved to be harmless, since such information offers a certain check against observations on living birds in the field. (See publications of the Biological Survey [q.v.] of the U.S. Department of Agriculture.) With few exceptions, the destruction of birds as a means of protecting crops, has been found to be an unsound policy.