THE DARWINIAN THEORY OF INSTINCT. 597 



developed carnivorous tastes — running about the trees, not to search 

 for nuts, but to search for birds, the blood of which it sucks. In 

 Ohinitahi there is a mountain parrot, which, before the settlement of 

 the place was a honey-eater, but, when sheep were introduced, the 

 birds found that mutton was more palatable to them than honey, and 

 quickly abandoned their ancestral habits, exchanging their simple 

 tastes of honey-eaters for the savageness of tearers of flesh. For the 

 birds come in flocks, single out a sheep, tear out the wool, and when 

 the sheep, exhausted by running about, falls upon its side, they bore 

 into its abdominal cavity to get at the fat which surrounds the kidneys. 



These, I think, are sufficient instances to show what I mean by local 

 variations of instinct. Turning now to the specific variations, I think 

 they constitute even stronger evidence of the transmutation of instinct ; 

 for where we find an instinct peculiar to a species, or not occurring in 

 any other species of the genus, we have the strongest possible evidence 

 of that particular instinct having been specially developed in that par- 

 ticular species. And this evidence is of particular cogency when, as 

 sometimes happens, the change of instinct is associated with structures 

 pointing to the state of the instincts before the change. Thus, for ex- 

 ample, the dipper belongs to a non-aquatic family of birds, but has de- 

 veloped the instinct, peculiar to its species, of diving under water and 

 running along the bottoms of streams. The species, however, has not 

 had time, since the acquisition of this instinct, to develop any of the 

 structures which in all aquatic families of birds are correlated with 

 their aquatic instincts, such as webbed feet, etc. That is to say, the 

 bird retains all its structural affinities, while departing from the family 

 type as regards its instincts. A precisely converse case occurs in cer- 

 tain species of birds belonging to families which are aquatic in their 

 affinities, these species, however, having lost their aquatic instincts. 

 Such is the case, for example, with the upland geese. These are true 

 geese in all their affinities, retaining the webbed feet, and all the struct- 

 ures suited to the display of aquatic instincts ; yet they never visit the 

 water. Similarly, there are species of parrots and tree-frogs, which, 

 while still retaining the structures adapted to climbing trees, have 

 entirely lost their arboreal habits. Now, short of actual historical or 

 paleontological information — which of course in the case of instincts 

 is unattainable, seeing that instincts, unlike structures, never occur in 

 a fossil state — short, I say, of actual historical or paleontological infor- 

 mation, we could have no stronger testimony to the fact of transmuta- 

 tion of instincts than is furnished by such cases, wherein a particular 

 species, while departing from the instinctive habits of its nearest allies, 

 still retains the structures which are only suited to the instincts now 

 obsolete. 



This last head of evidence — that, namely, as to local and specific 

 variations of instincts — differs in one important respect from all the 

 other heads of evidence which I have previously adduced. For, while 



