CONSERVATION OF BIRDS 375 



after the egg has segmented (divided into many cells) the embryo 

 may be seen developing on one side of the egg. The rest of the 

 egg is made up of food or yolk and when the baby fish hatches 

 it has the yolk attached to its ventral surface for some time. 

 Eventually the food is absorbed into the body of the fish. (Figure, 

 page 372.) The young fry are kept under ideal conditions until 

 later, when they are shipped, sometimes thousands of miles, t( 

 their new homes. 



Reasons for Conservation of Birds. — We have already learned 

 that birds, with few exceptions, are of very great value to man, 

 through their destruction of weed seeds and of insects harmful to 

 crops. But in spite of this fact, many species of birds have been 

 almost exterminated in this and other countries, and the total 

 number of birds has decreased to an alarming extent. This has 

 been due largely to killing for food and " sport," and for plumage. 

 A few decades ago, the spraying of trees was unknown ; to-day 

 $10,000,000 or more a year is spent for labor and sprays ! It is 

 estimated by Dr. Hornaday of the New York Zoological Park, that 

 a yearly toll of $520,000,000 now collected by insects might be 

 saved if we had as many birds as formerly. 



The American passenger pigeon, once very abundant in the 

 Middle West, is now extinct. Audubon, the greatest of all Ameri- 

 can bird lovers, gave a graphic account of the migration of a flock 

 of these birds. So numerous were they that when the flock rose 

 in the air the sun was darkened, and at night the weight of the 

 roosting birds broke down large branches of the trees in which they 

 rested. To-day not a single specimen of this pigeon can be 

 found, because they were slaughtered by the hundreds of thousands 

 during the breeding season. The wholesale killing of the snowy 

 egret to furnish ornaments for ladies' headwear is another example 

 of the improvidence of our fellow-countrymen. It was killed 

 during its breeding season ; and for every egret killed, an entire 

 bird family was blotted out of existence. Prairie chickens are 

 unknown in many states where they were abundant before 1900. 

 The same thing will happen to the quail where it is unprotected. 



Hawks, owls, shrikes, crows, and jays all play a small part in the 

 destruction of our native birds. The English sparrow has done 

 great harm in driving away useful birds. Squirrels and particu- 



