WOOD NOTES WILD. 67 
It is generally believed that the booming is made with 
the mouth, but careful investigation has convinced me 
that the mouth has nothing to do with it. This peculiar 
sound is produced by the pointed wings, stretched down 
and firmly set, cutting the air. Perhaps it is true that 
only the males indulge in this singular exercise. 
Though the night-hawk and the whippoorwill are often 
taken for one and the same bird, the night-hawk never 
sings “ whippoorwill,” nor does the whippoorwill ever 
“boom.” The whippoorwill has bristles on each side of 
the mouth, and a rounded tail, while the night-hawk has 
a forked tail and no bristles, and the plumage is dif- 
ferently marked. Both have the singular habit of sitting 
lengthwise of a limb. 
