158 THE STORY OF THE BIRDS. 
wrens, and White, of Selborne, notes that while the 
fieldfare nests in trees it sleeps upon the ground. It 
is of course well known that some parrots suspend 
themselves head downward from boughs during sleep 
and that others sleep hanging by the hooks of their 
beaks on the insides of cavities. Swifts and wood- 
peckers sleep in cavities usually in the upright posi- 
tion, braced by toes and spinous tail feathers. 
> iy «alia 

Lodgings for the little birds. 
As noted, the Passeres all sleep sitting, though 
some squat on the ground. It is not possible to at- 
tempt here the roosting habits of all such as are known 
even, and some general statements must suffice. 

