60 BIRDS ORGANIZATION DIAGRAM 4. 



Birds which live on soft insects instead of corn, have no gizzard, 

 or at least its surface is not so thick, and it does not contain any 

 stones. 



Birds breathe like mammals by a windpipe and lungs. They 

 have also a larynx in the throat above the windpipe, but they 

 have also another in the chest, at the point where the windpipe 

 divides into two branches to conduct the air to each of the lungs. 

 It is by this second larynx that a duck can still utter a cry after 

 its head has been cut off. While some birds have a very 

 disagreeable voice, others sing, or can imitate the human voice, 

 like tiie parrot, the starling, and the jay. 



Birds have the best sight of all animals ; and a hawk flying at 

 a great height in the air can easily perceive a shrew-mouse or a 

 field-mouse running in the grass, and dart upon it ; it is then 

 said that it pounces on its prey. Birds have generally only a 

 hole for an ear ; but some, like the owls, have a very large ear, 

 as large as that of a little child, hidden in the feathers on the 

 side of the head. 



Birds' feathers are useful for a great many purposes for 

 pens, for beds, and for ornament. These feathers are often very 

 finely coloured, and in some birds they vary with the seasons. 

 Many birds have more brilliant plumage in spring than during 

 the remainder of the year, and the bird is then said to have 

 assumed its nuptial plumage. 



All birds lay eggs. They are white in the fowl, but coloured 

 or spotted in most other birds. We notice in the egg, 1st, 



^r"ggg^ the shell, which is hard 



Germ. y'd^mKHfaf Airchamber. j . , ~ , ., 



-MSB IraS Y Ik resistant ; 2nd, the 



g , .^-JSJ9 lHf_r Wh't white, formed of albu- 



men, which has the 



property of hardening, when heated nearly to the temperature of 

 boiling water ; 3rd and last, the yolk, on which we observe a small 

 paler spot, which is the germ. The yolk also hardens when 

 heated. When a fresh egg has a hole carefully made in it, so 

 that the yolk is seen in its position, we discover that it is 



