ADELIE PENGUINS 



I have said very well, whilst Fig. 61 shows a mother 

 with a chick twelve days old. 



Whilst the chicks are small the two parents 

 manage to keep them fed without much difficulty;* 

 but as one of them has always to remain at the 

 nest to keep the chicks warm, guard them from 

 skuas and hooligan cocks, and prevent them from 

 straying, only one is free to go for food. Later on, 

 however, two other factors introduce themselves. 

 The first of these is that the chick's downy coats 

 become thick enough to protect them from cold 

 without the warmth of the parent ; and the second 

 that as the chicks grow they require an ever- 

 increasing quantity of food, and at the age of about 

 a fortnight this demand becomes too great for one 

 bird to cope with. At this time it is still necessary 

 to prevent the chicks from stra5dng and to protect 

 them from the skuas and " hooligans," and so to 

 meet these two demands a most interesting social 

 system is developed. The individual care of the 

 chicks by their parents is abandoned, and in place 

 of this, colonies start to " pool " their offspring, 

 which are herded together into clumps or " er^ches," 

 each of which is guarded by a few old birds, the 

 rest being free to go and forage. 



* Fig. 62. 



96 



