THE HONEY-GUIDES 163 



taken at Rustenberg, Transvaal, on January 6, was in a more advanced 

 stage of the postjuvenal molt. 



The postjuvenal molt begins on the throat and in the remiges, and 

 seems to end with the feathers of the upperparts. 



Guiding 



It is in this species that the guiding habit is best developed, far 

 more so than in /. variegaius, the only other honey-guide known to 

 lead to bees' nests. The behavior involved in guiding is so unusual 

 and remarkable as to have brought into the literature much descrip- 

 tive writmg, frequently of doubtful value; indeed, the popular con- 

 ception of guiding is, as intimated in the introduction to this report, 

 overly simplified and generally naively interpreted. The whole sub- 

 ject of guiding has been discussed earlier (on pp. 25-71), and at this 

 point we may merely stress again the fact that there is no occasion 

 whatever to assume anything involving planning or intelligence on the 

 bird's part. The behavior is wholly on an instinctive level, but it is 

 something sought for by the bird, not merely something it does auto- 

 matically when the necessary stimuli are present. Precisely because 

 so many statements in the literature are poorly phrased with verbal 

 intonations implying foresight or similar mental activity on the part 

 of the honey-guides, I have taken great pains to gather together as 

 many reUable bits of information from other observers and from the 

 literature as possible, and to make specially planned and oriented 

 field observations myself. These are given in the chapter referred 

 to above. 



Food and Feeding Habits 



Adult: Analyses of the stomach contents of many adult birds col- 

 lected reveal masses of beeswax, poUen, what seems by the odor to 

 be honey, larval and adult bees, other insects such as winged termites, 

 beetles, and ants, insect eggs, and occasional vegetable matter. Inas- 

 much as the food obtained from bees' nests has been assumed to be 

 the benefit the bird derives from its guiding behavior, these items de- 

 serve special comment. It may be noted, however, that hunger is 

 not necessarily the immediate, driving factor in causing a bird to 

 guide, as evidenced by two examples I shot at the end of guiding trips 

 but before the bees' nests were opened — both specimens proved to 

 have well filled gizzards. In Rhodesia, Plowes also found a guiding 

 bird to have a well filled gizzard. From my own observations, and 

 as far as I can judge by the experience of others communicated to me 

 either directly or in published data, it appears that even in areas where 

 the birds indulge most frequently in guiding they get a large propor- 

 tion of their food without the aid of human, or, as far as we know, 



309265—55 1? 



