Wings 333 
that this restriction and disuse have been to subserve some 
good and useful purpose,—food perhaps being more easily 
obtained, or enemies avoided by terrestrial or aquatic 
locomotion. Functional radiation, working always for 
the good of the race, once gave to all birds the power of 
traversing the globe, passing high over sea and land; but 
later this was withdrawn, until in some cases their wings 
have become a mockery. The wings of the Owl Parrot 
of New Zealand are of full size, but the muscles are so en- 
cased in fat that they are useless for flight. These par- 
rots feed on ground-mosses, and being nocturnal and 
tnerefore having few enemies, their only use for wings 
is occasionally to sail gently to earth, like a Flying Squir- 
rel, from the trees in the hollows of which they some- 
times roost. For this purpose their flabby muscles are 
perfectly suited. 
The Spotted Tinamou of South America is one of a 
number of birds which have not quite lost the power of 
flight, but in which, as in the first attempts of a young 
bird, almost no control is possessed over the direction 
or height of their flight. In fact, the condition is much 
the same as that of a man in an ordinary balloon, who 
is at the mercy of the wind and the sustaining power of 
the gas. Hudson gives the following interesting account 
of this bird: “It is an exceedingly rare thing to see this 
bird rise except when compelled. I believe the power 
of flight is used chiefly, if not exclusively, as a means of 
escape from danger. The bird rises up when almost trod- 
den upon, rushing into the air with a noise and violence 
that fill one with astonishment. It continues to rise 
