FAGGING IN THE BIRD WORLD 47 



of revenge, and the honey-guide must be a 

 very intelligent bird, for it has to learn its 

 trade quite by itself, since it is one of the 

 birds which are brought up, not by their 

 own parents, but by other species of birds, 

 as our cuckoo is. The habits of these " para- 

 sitic " birds, who put their young ones out as 

 boarders, give another example of the way 

 in which some birds make others work for 

 them, but they are so curious and remarkable 

 that they must have a chapter to themselves. 



