258 POULTRY AND WILD BIRDS 
Shape of the Tail. — Most commonly the end of the tail is 
more or less rounded, but in some birds it is perfectly square. 
Again, the middle feathers may be shorter than the outer 
ones, and we then say the tail is notched, or slightly forked, 
or deeply forked, according to the 
depth of the indentation. 
The Feathers. —'The main feathers 
of the tail are strong, stiff quills, like 
those of the wing, and the bases of 
these quills are covered by shorter 
feathers, called upper tail coveris and 
lower tail coverts. When the tail is 
used in climbing, as in the Woodpeck- 
ers, the ends of the feathers come to a 
sharp, stiff point ; in case of the Chim- 
ney Swift, the stiff midrib or stem 
even extends beyond the web of the 
feather. The quills are set in a single 
Various Forms or Bmp row. The number varies slightly, but 
TalLs in all perching birds it is twelve. 
a, Catbird; 6, prairie 
sharp-tailed grouse; c, bank Tue VoIce 
swallow; d, barn swallow ; 
dy it tol Ne Thee henna 
creeper. 
our notice as their songs. All birds 
have call notes, but some are very meagerly gifted, while 
others seem able to express alarm or give the signal to take 
wing, or on the other hand, to voice the spirit of content- 
ment and sociability. 
Song. — The power of song is limited to the Perching 
Birds, and not even all of these have it. Furthermore, it is 
generally restricted to the male of the species, and is employed 
