42 Habit and Instinct. 



note, and ran off. Then I threw in more edible cater- 

 pillars, which again were eaten freely. The chicks had 

 thus learnt to discriminate by sight between the nice and 

 the nasty caterpillars. Similarly, moorhen chicks rapidly 

 discriminated between small edible beetles and soldier 

 beetles. Such discrimination is, however, not congenital, 

 but acquired. The young birds do not for some little time 

 avoid pecking at their own fresh excrement, though this is 

 obviously distasteful. 



The cinnabar caterpillars are, as I have said, con- 

 spicuously marked with alternate yellow and black rings. 

 It would seem that the end of this conspicuousness is to 

 render association in the individual experience of young 

 birds more rapid and more certain ; there does not appear 

 to be any congenital and instinctive avoidance of such 

 caterpillars with warning colours. Young moorhens 

 found the conspicuously marked burnet moth distasteful, 

 the obnoxious part being the wings, for the body from 

 which the wings were removed was eaten with apparent 

 relish, while the severed wings were rejected with evident 

 signs of distaste. I was desirous of ascertaining whether 

 the different appearance of brandlings (Lumbricus fcetidus) 

 and other small worms was sufficient to enable the moor- 

 hens to distinguish them, but this was apparently not the 

 case. The experiment showed, however, the marked in- 

 fluence of the first experience. For the moorhen which was 

 given a brandling first was long before he would touch any 

 worm, while that which was given a brandling after several 

 less highly flavoured worms, though he was rendered a 

 little suspicious for a time, picked up each cautiously and 

 rejected or swallowed it according to the taste. A few days 

 later, however, both moorhens would eat brandlings when 

 they were hungry. 



My observations with regard to the effects of giving 



