The Honey-guides 



Introduction 



The honey-guides are a small family of picarian birds related to the 

 barbets, the woodpeckers, and the toucans. The family contains 

 eleven species classified in four genera. All but two of these species 

 are found only in Africa south of the Sahara— the two exceptions 

 are Asiatic in distribution, one in the Himalayas, and one in Burma, 

 Siam, Mala3^a, Sumatra, and Borneo. These birds, of plain colora- 

 tion and small size, are of unusual interest to the student of behavior 

 because they are parasitic in their breeding habits and because one 

 section of the family has developed a most remarkable symbiotic 

 relationship \vith certain mammals — ratels and humans — by "guiding" 

 them to wild bees' nests. It is this habit in the best known species 

 of the family that has given the group its common name, honey- 

 guides, and also its technical one, Indicatoridae. The problems 

 arising from these two aspects of the life histories of these birds could 

 not even be approached intelligently until more factual data were 

 amassed and interpreted, and it was to make this possible that the 

 present study was undertaken and this report written. An example 

 of one of these problems may make this clear. 



Prior to this study, the impression one received from the literature 

 was that the honey-guides fed largely, if not wholly, on bee comb and 

 its inclusions (bee larvae, eggs, and honey), but that the birds could 

 not open the wild bees' nests by themselves and therefore had to depend 

 on the aid of ratels and humans, which they "guided" to these poten- 

 tial stores of food. In other words, guiding was thought to be the 

 chief food-getting method used by the bnds. To the thoughtful 

 student of animal habits this posed a disturbing problem. Habits, 

 like structures, have their long and involved evolutionary history — a 

 history which can be reconstructed mainly on the evidence for "selec- 

 tive values" in their successive stages. But a habit such as this, 

 whose only apparent use to the bnd depends entirely on the coopera- 

 tion of two wholly separate and independent creatures (bird, and ratel 

 or human) cannot have had any conceivable value until it was perfected 

 by both participants, and perfected in such a way as to be of benefit 

 to the bird. Incipient or intermediate stages in its development 

 would seem to have been quite useless; it was an "all or nothing" 

 situation. It followed that either the literature was misleading and 

 that the picture of the guiding habit was wrongly expressed, or that 



