CONSERVATION AND ITS MEANING 599 



artificial propagation is hard to determine, it is believed that it has 

 been moderately successful. The Bureau is also attempting to raise 

 the glochidia in artificial media in quantities large enough to make it 

 possible to keep the supply from being depleted by the pearl button 

 industry. Here again hope lies in the work of the biologist who must 

 solve the problem. 



Birds 



In the matter of bird life the story is the same. The American 

 passenger pigeon, which once was so numerous that in 1869 one town 

 in Michigan marketed 11,880,000 pigeons in forty days, became 

 extinct by 1914. In early Colonial times the heath hen was abundant 

 along the eastern coast from Maine to the Carolinas. The last sur- 

 viving member of this species died on Martha's Vineyard Island in 1932. 

 The snowy egret has been practically exterminated in the South and 

 the prairie chicken has suffered the same fate in the Central West. 

 Unless adequate protection is given, the red-head, canvasback, and 

 ruddy duck may become exterminated at least in parts of their 

 range. The Labrador duck was exterminated in 1875, a victim of 

 reckless exploitation. Measures have been taken to protect the 

 dangerously depleted wood duck, which is now, under a closed season 

 extending over some years in certain states, showing a hopeful though 

 slow increase in numbers. 



The relation of bird migration to conservation, as in the case of 

 fishes, is close, for the annual journeys that birds make have been 

 made use of by sportsmen in shooting duck and other wild fowl. 

 While biologists have been trying to explain, with a certain amount of 

 success, the factors back of bird migration, an army of hundreds of 

 thousands of licensed hunters, with very definite success, have been 

 slaughtering migrating birds by millions, until today many of our 

 wild fowl are in imminent danger of extermination. Dr. William T. 

 Hornaday ten years ago estimated that the stock of game birds and 

 quadrupeds left at that time was only about 2 per cent of what had 

 existed fifty years before, and today even this remnant has been 

 greatly reduced. A carefully planned program of restoration of 

 breeding and feeding areas, destroyed by drought, cultivation of the 

 land for crops, or by other agencies, is now being carried out by the 

 Federal government in certain localities in the United States, where 

 not many years ago water and shore birds could be found in great 

 numbers. Sportsmen are combining with agencies seeking a biolog- 

 ical approach to the problem. 

 H. w. H. — 39 



