CHAPTER XII 
THE BODY OF A BIRD 
N experimenting with balloons and flying-ma- 
chines, weight is a question of prime import- 
ance, and among birds there seem to be certain 
limits to the bulk of the body, beyond which flight is 
impossible. The tiny hummingbirds, with bodies weigh- 
ing less than some insects, have remarkable powers of 
flight, and throughout all the groups of larger birds we 
find certain species with exceptional flight ability, until 
in the birds of widest extent of wing, such as the condor 
and the albatross, flight seems to reach the acme of perfec- 
tion. But the flying birds of actual heaviest bulk are 
perhaps the Wild Turkey, the Great Bustard, and the 
Trumpeter Swan, the two latter reaching weights of thirty- 
two and twenty-five pounds respectively. Even the 
gigantic Pterodactyls, those flying reptiles of olden time, 
some of which had heads a yard long, and an expanse of 
eighteen feet or more of bat-like wings, are estimated 
to have weighed but twenty pounds or thereabouts. 
But when the necessity for flight ceases, a bird may 
begin to assume larger proportions and greater weight 
without detriment; just as a mammal which adopts a life 
in the dense medium of water may attain a much more 
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