112 HOW HE IS MADE 
of no use whatever, and the birds cannot fly 
at all. This has happened, it is supposed, to 
the ostrich family and to some 
birds living in the sea. 
ae The tail of a bird is formed of 
an equal number of feathers in 
pairs, most often twelve. When 
spread they are the shape of a 
fan (Fig. 13), and when closed they he over 
each other with the middle pair on top. 
The tail feathers are not always of the same 
length, and that makes a difference in the shape 
of the end. Sometimes they are even (like Fig. 
Fic. 14. 
Tail of Vireo. 

Fig. 15. 
Tail of Swallow-tailed Kite. 
14), when the tail is said to be “square.” 
Sometimes the middle feathers are a little longer 
than the outside ones, and then it is “ rounded” 
