QUADRUPEDAL LOCOMOTION 27 



of soaring ability ; but Buller, in his " Birds of 

 New Zealand," mentions that the immature speci- 

 mens of the very common Harrier of that country 

 {Circus gouldi), which are more conspicuously diflEer- 

 ent in colour from the adults than are the young 

 Indian Kites, do not soar as the old ones do, so 

 that they are often taken for a diflEerent species of 

 Hawk altogether. 



In very rare instances young birds may even fly 

 better than adults ; this is the case, according to 

 Mr. W. H. Hudson, -with the common Tinamous 

 of Argentina ; and in that very curious bird the 

 great grey Steamer-Duck of the coasts of southern 

 South America (Micropterus cinereus), only the 

 younger individuals seem to be able to fly at all, 

 the older birds becoming so heavy that their small 

 wings simply serve to support and assist them when 

 running on the surface of the water, a curious 

 quadrupedal mode of locomotion which has attracted 

 the attention of all observers, but seems only to 

 have been fully and exactly described by Mr. M. 

 NicoU in his admirable work on his experiences as 

 a naturalist in the cruises of the Earl of Crawford's 

 yacht the Valhalla. So fast can these huge Ducks 

 " steam " along, he tells us, that a six-oared boat 

 cannot overtake them or even come within shot. 



Quadrupedal locomotion on land is found in the 

 case of the Penguins, which when pressed will use 

 their flipper-wings as fore-legs, the species which 

 inhabit snowy regions tobogganing along most 

 eflEectually in this way. As we shall see later, also, 



