286 The Bird 



gigantic size than one which has to support its body in 

 the thinner atmosphere: a whale is to a horse as an 

 ostrich is to a dove. 



The ostrich is the largest of all living birds, a full- 

 grown male being able to reach to a height of nine feet 

 and weighing as much as three hundred pounds; but 

 even these figures were exceeded by its extinct relative 

 of Madagascar, the moa, whose height is variously esti- 

 mated at from ten to eleven feet, and whose massive leg- 

 bones show that its weight must have been much greater 

 than that of the ostrich. 



There is a great difference in the relative condition 

 of the body in various birds. Herons, even when fish 

 are abundant, with opportunities of feeding from morn- 

 ing to night, are thin to emaciation. Truly they belong 

 to the ''lean kine." A fat heron would be an anomaly. 

 On the other hand, the flesh of many sea-birds seems as 

 constantly encased in thick, oil}' layers of fat. Petrels 

 are used by the inhabitants of some islands as candles, 

 simply by threading the body of the dead bird with a 

 wdck, the excess of fat burning steadily until the whole is 

 consumed. Penguins are well protected against the icy 

 waters of their Antarctic home by a layer of fat under 

 the skin, so thick in proportion to their size as to remind 

 one of the blubber of whales. 



If we were writing of the bodies of the fur-bearers 

 instead of birds, we would have much to say concerning 

 the various kinds of scent-glands and secreted odours; 

 but in birds the only gland is that above the tail, which 

 furnishes the oil with which the bird preens its plumage, 



