EVOLUTION OF BIRD-SONG 



much resembles that of a species of tree-frog which 

 frequents the same tree, that it is sometimes difficult 

 to distinguish the one from the other " (Wilson, op. 

 cit. vol. i. p. 148). It has been stated that the voice 

 of the ostrich is a roar so like that of the lion that 

 even Hottentots have been sometimes unable to 

 discriminate between them. The sounds are cer- 

 tainly somewhat similar. The cry of the ostrich, 

 like that of the Australian emu, is a deep, hollow, 

 rumbling sound. Wilson said that the note of 

 the American burrowing owl (Speotyto cunicularid) 

 " is strikingly similar to the cry of its companion the 

 marmot, and sounds like cheh cheh, pronounced 

 several times in rapid succession ; and were it not 

 that the burrowing owls of the West Indies, where 

 no marmots exist, utter the same sounds, it might 

 be inferred that the marmot was the unconscious 

 tutor to the young owl ; this cry is only uttered as 

 the bird begins its flight" (op. cit. vol. iii. p. 225). 

 The South African jackal buzzard (Buteo jackal} 

 has a cry "singularly like that of the common 

 jackal, whence its name" (Layard, op. cit. p. 27). 

 Verreaux's eagle owl (Bubo lacteus) utters a " call- 

 note which is often mistaken for that of the leopard " 

 (pp. cit. p. 71). Persons who have not been near cattle 

 grazing rank grass at night will think it absurd to 



