Intelligence and the Acquisition of Habits. 159 



It is, however, a practical problem of no little difficulty 

 to determine in particular instances whether a given 

 adaptive activity is an instinct or a habit; whether it 

 is congenital in its definiteness, or has acquired this 

 definiteness by intelligent selection and recurrent repetition. 

 The observations which have been described in preceding 

 chapters had for one of their objects, the determination of 

 this point for some of the activities of bird life. Let us 

 now take a particular case — for such a case is both more 

 instructive and more interesting than mere generalities — 

 by which the difficulty in question may be further 

 illustrated. 



In 1874 Darwin drew attention, in the columns of 

 Xature,* to the fact that primrose flowers were cut off, and 

 a piece of the calyx, between one- and two-tenths of an inch 

 in length, was removed. He attributed the destruction to 

 birds, who would thus obtain the nectar contained in the 

 flower, but asked for further information. 



Many letters appeared in response to Darwin's appeal. 

 Among them one by Major E. R. Festing, who said,f 

 "A month ago I saw a caged hen bullfinch that would 

 treat any quantity of primroses which were given her in 

 precisely the way described by Mr. Darwin. She gave 

 one snip only to each flower, not again touching the 

 remains of it, which fell to the floor of the cage." And 

 other evidence pointed to the bullfinch as the bird which 

 possessed this habit. 



Darwin returns to the subject in a subsequent number,^ 

 and writes as follows : " It is clear that the ovules are the 

 chief attraction ; but the birds, in removing by pressure 

 the ovules, could not fail to squeeze out the nectar at the 

 open end, as occurred when I squeezed similar bits between 



* VoL ix. p. 482. t Nature, vol. x. p. 6. 



X IbicL, toL x. p. 24. 



