EVOLUTION 993 



Life-sciences — the organic, the social, and the psychological and 

 ethical with these — cannot but thus boldly re-express this ancient 

 ideal for Humanit}^ (indeed with all the other forms of life it can 

 associate), as Etho- Polity, of Parnassolympians, in Eutopia. 



CHANGES OF BEHAVIOUR AND REACTION AMONG 



LIVING ANIMALS 



One of the characteristics of life is plasticity; but it is not always 

 in the same way that living creatures become suited to new circum- 

 stances. Sometimes an intelligent change of habit is effected very 

 rapidly. Thus it is not more than a century since sheep were taken 

 to New Zealand, but in less than that time the naturally vegetarian 

 or frugivorous Kea parrot (Nestor notahilis) has learned how to tear 

 away the fleece from the loins and get at the fat and flesh above the 

 kidneys. They usually attack sickly or fallen sheep, but they some- 

 times kill normal animals, and in either case the new habit is a very 

 remarkable one. Some suggest that the big-brained birds mistook 

 resting sheep for moss-mounds, in which they are said to dig for 

 insects ! More probably the birds may have begun by pecking at the 

 fat adherent to sheep-skins pinned out to dry. Many discoveries 

 among animals (much as in mankind) are thus made half-fortuitously ; 

 and intelligence is shown in the way the discovery is appreciated 

 and utilised. Big-brained birds like parrots are not slow to take a 

 hint, and the new device would probably spread by imitation. 



Change of Diet in Gulls. — ^The Herring Gull and the Lesser 

 Blackbacked Gull are characteristically fish-eaters; but it has been 

 well known for a long time that they are not averse to eating corn 

 in the harvest fields. But this tendency to v^egetarianism has become 

 increasingly marked in Scotland during the twentieth century. Two 

 or three hundred gulls may be seen busy among the stooks on a 

 single field of corn, and they also gouge out the insides of turnips 

 in a systematically disastrous way. They will even dig up potatoes 

 near the surface. The chief reason for this inland vegetarian feeding 

 is probably that the numbers of Herring Gulls and Lesser Black- 

 backs have greatly increased, partly through protection, and partly 

 because the birds of prey that used to devour the young have become 

 scarce. The White-tailed Sea-Eagle is no longer to be found in 

 Scotland; the Raven has practically gone, and the Peregrine Falcon 

 is rare. It is probable that the increase of trawling has restricted the 

 readily available fish-supply for Herring Gulls and Lesser Black- 

 backs; and this would naturally suggest to shrewd birds the 

 exploration and exploitation of other fields. So there has been, to 

 man's loss, an intelligent and rapid change of habit. It may be 

 noted in passing that the multitudes of small Blacldieaded Gulls 



VOL. II s 



