CHANGES IN FEEDING 65 



may simply be due to its being, like the eagle- 

 billed Pesquet's Parrot, an unspecialized early form. 

 Its reversion to a vegetable diet in captivity may 

 point the same way ; in any case it is instructive 

 to notice, that, unspecialized as it is, its beak has 

 at any rate a good share of typical Parrot power, 

 judging by its exploits in the way of gnawing wood. 

 I have also seen, when a couple were kept in a 

 cage in the indoor parrot-house at the Zoo, one 

 cracking canary-seed, while the other amused itself 

 by levering up the perch in the next cage hard 

 alongside, for the discomfiture of the inmates. 



The Kea's is not only the most notorious, but 

 really the most remarkable change of diet known ; 

 but minor changes are often recorded, and though 

 these are often brought about by man's interference 

 in producing a new food-supply or in transporting 

 birds from one country to another, they must not 

 be despised as unworthy of study on that account, 

 since in undisturbed Nature the equilibrium we 

 hear so much about is not constant. Birds colonize 

 areas on their own initiative occasionally, and 

 plants even invade new habitats as circumstances 

 become more favourable for them, so that there 

 are always opportunities for changes of diet. 



Mr. Hudson has recorded how, since the giant 

 grasses of the Argentine pampas have given place 

 to the turf-making grasses and clovers of Europe, 

 the Chaja or Crested Screamer (Cbauna ckavaria), 

 which used to feed on water-plants, has taken to 

 grazing on land ; it is a curious thing that the 



5 



