Proceedings. 57 



Another bird which illustrates the adaptive faculty is the 

 Starling. When your grapes are rij)ening he will attack 

 them, but his ordinary food is some sort of grub which he 

 gets in the pastures ; at the same time on any warm day 

 between April and October he may be seen hawking for flies, 

 like a somewhat maladroit Swallow. One can without diffi- 

 culty imagine circumstances under which the Starlings of 

 Great Britain, which I believe do not migrate, might be com- 

 pelled to elect between starvation and a summer diet almost 

 exclusively of insects caught on the wing. Under such cir- 

 cumstances one would expect a great decrease in their 

 numbers, but a survival of the species, the wing and tail 

 being probably modified in the course of many generations. 

 That the alternative which would be fatal to many other spe- 

 cies would be fatal to the Starling one can hardly believe. 

 One is but too apt to consider that a change of habit or 

 mode of life in a species must be by slow degrees ; but there 

 is good evidence that this is not always the case, as I have 

 shown, and certain undisputed facts go to prove that so 

 important a revolution as a change of diet from vegetable to 

 animal food is sometimes effected per saltum. 



The great Ground Parrot of New Zealand is believed to 

 have been confined to a vegetable diet, fern-roots belike, or 

 such-like harmless matters, until the introduction of sheep 

 some forty years since, when the bird developed an extra- 

 ordinary taste for mutton. For the sake of Science it is 

 almost a pity that so interesting a problem was not permitted 

 to work itself out; an islet might have been stocked with 

 Sheep and Parrots, and carefully guarded from intruding 

 naturalists and wool-staplers for, say, a century. "What 

 would have been the result is now of course impossible to fore- 

 cast, but had the supply of Sheej) supported a stock of Parrots 

 it is not unlikely that so great a change in fare would have been 

 followed by further changes in plumage, bulk, and weapons. 



Although this instance stands alone, as far as I know, with 

 regard to the size of the quarry marked out for food by the 

 new carnivorous instinct of the bird, yet it is not without 

 bearing upon the question that a fowl will sometimes run 



