VERTEBRATA : AVES. 621 



make their nests in holes in trees, and in the rocks. Their 

 natural voice is harsh and grating. The true Parrots (Pstttacus) 

 are mostly inhabitants of tropical America, and their prevailing 

 colour is green. Other well-known forms are African. The 

 Cockatoos (Plyctolophus], the Love-birds (Agapornis), and the 

 Lorikeets (Trichoglossus) belong to the Melanesian and Austra- 

 lian province. The Lories (Lorius) inhabit the Melanesian 

 province. The true Macaws (Araince) are exclusively Ameri- 

 can ; and the true Parrakeets (Pezoporince) are exclusively con- 

 fined to the eastern hemisphere, being especially characteristic 

 of Australia. 



Fig- 343. Head of Cockatoo. 



Among the more remarkable of the Psittacidtz may be men- 

 tioned the singular "Kakapo" (Strigops habroptilus] of New 

 Zealand, which makes an approach to the Owls. This curious 

 Parrot differs from the ordinary members of the order in not 

 being gregarious in its habits, in only being active by night, in 

 forming burrows in the ground, in which it spends the day, and 

 in being limited in its powers of flight. One species of Parrot 

 (Lophopsittacus Mauritianus) has become extinct during the 

 human period, and the Philip Island Parrot (pfestor productus}, 

 of the New Zealand province, has not been known to occur since 

 the year 1851. 



In the next family of the Scansores are the Toucans (Rham- 

 phastidce), characterised by having a bill which is always very 

 large, longer than the head, and sometimes of comparatively 

 gigantic size (fig. 344). The mandibles are, however, to a 

 very great extent hollowed out into air-cells, so that the weight 

 of the bill is much less than would be anticipated from its size. 



