THE HONEY-GUIDES 131 



duration similar to that produced by a person holding a wooden slat 

 against the spokes of a fast-revolving wheel. After about two min- 

 utes of this it flew up high and went off. The observer was unable 

 to see just which bird made the sound, but inasmuch as he had heard 

 the noise on other occasions he is of the opinion that it has something 

 to do with mating, and that it is probably the female that is respon- 

 sible for it. He is also of the opinion that the noise is made by the 

 wings, not the taU. 



The observations of Ranger, Neuby-Varty, myself, and a few others 

 all suggest, but do not prove, that the rustling is made by the wings. 

 However, the observations of Wood (1940) in Nyasaland suggest that 

 it is the tail feathers and not the wings that are involved. Further- 

 more, in his case the rustling flight was more of a series of downward 

 swoops than of fairly deep undulating dips in a circular flight. His 

 account may be presented in his o^vn words. 



Walking along one morning ... I suddenly became aware of a very curious 

 deep drum-like sound which lasted for a second or two at a time, seemingly 

 somewhere in the air around me. Bvooommm — pause — Bvooommm, with a 

 marked accent on the ooo sound decreasing on the final mmm. It seemed a distinct 

 vibration of the air. 



Looking around, I could see nothing to account for it, and it was hard to de- 

 termine exactly where it came from. I was in a somewhat open spot, a little 

 away from the trees, and every minute or so the sound was repeated. It was 

 fleeting and rather uncanny! I therefore stopped and stood dead still, very much 

 awake now and on the alert. The author was soon spotted. Down from the 

 top of the nearest big tree a Honey -Guide swooped towards me at tremendous pace, 

 dropping to just above my head and then zooming upwards again to the same tall 

 tree or another nearby. As it neared me and turned the tail-feathers were out- 

 spread wide apart, and the deep drumming bvooommm sound vibrated in the air. 



No other call was uttered by the bird at the time, but with my field glasses I 

 soon identified it as it sat on the tree in the intervals of these swoops. Thinking 

 that the observation was somewhat out of the common in the behaviour of Honey- 

 Guides, I shot the bird for absolutely definite certainty of identification and pre- 

 served the skin, which was of a male. 



I may mention that this same method of attracting attention was heard by me 

 several times subsequently in that district, but I have not remarked it elsewhere 

 so far as I can remember. More often, of course, the birds simply uttered their 

 usual well-known calls for attracting attention, which I may write as Wit-purrr 

 and the excited chattering Churrr or Tchuk-tchuk-tchuk-tchuk-tchuk. 



1 feel convinced that the bvooommm sound is produced entirely by vibrations 

 set up by the force of the air passing through the out-spread tail-feathers, and 

 that it is certainly not a vocal call. 



Wood quite rightly compares this performance with the well kno'wn 

 drumming of the snipe, which is definitely known to be caused by the 

 rush of air between the narrowed outer rectrices. There is nothing 

 peculiar in the shape of these feathers in the greater honey-guide as 

 there is in the case of the lyre-tailed Melichneutes. 



309265—55 10 



