THE HONEY-GUIDES 241 



horizontally for a time. However, there was a difference this time; 

 the bird suddenly interrupted its noisy plunging, which was in loose, 

 small spirals, to reascend silently and then to dive again farther away. 

 Each time the hein-hein note was heard it corresponded well with the 

 movement of the bu*d, but it was impossible at that distance to dis- 

 tinguish clearly what the bird was doing with its remiges and rectrices. 

 A quarter of an hour later it rose a second time from the forest, and 

 climbed very high, in spirals as usual, and then fell, noisily flapping its 

 wings and spreading its tail. Six more performances were observed 

 that morning. It was noted that the tail was opened widely during 

 the noisy descents. The descent, usually preceded by a rather abruptly 

 curtailed circling flight, was usually not quite straight, but also in- 

 volved something of a spiral. The noise accompanying the descent is 

 one that carries well beneath the forest canopy, above which the action 

 is taking place. 



The shortest duration of a complete soaring and diving performance 

 varied from one to two minutes, the plunge itself not exceeding more 

 than thirty seconds. The performance seems to take place chiefly on 

 dark or overcast days; the bird m.ounts far into the air and then lets 

 itself drop very swiftly, and as it descends it opens and closes its wings 

 and tail rapidl}^, producing a sonorous vibration. While this noise is 

 strong and carries well, it does not help one to find the position of its 

 maker; it is very difficult to locate its author because its gliding is of 

 dizzying speed. The accompanying diagrams of the paths of two 

 such flight performances (fig. 6) are taken from Rougeot's paper. 



The role of this performance is as yet uncertain. In other birds 

 with comparable aerial evolutions, such as some snipe, larks, and 

 others, there is often a connotation of courtship display involved. 

 Thus, Armstrong (1942, pp. 255-256) mentions several different kinds 

 of sounds produced mechanically by wing or tail feathers during such 

 flights, and points out that while "the noisy flapping of agitated lap- 

 wings often appears to have an intimidatory rather than a courtship 

 function . . . Other performances are more definitely in the nature 

 of advertisement; the airy drumming of the snipe and the black- 

 throated honey-guide . . . the humming glide of the southern dunlin, 

 the roaring descent of the black-tailed godwit, and the boom of the 

 American nighthawk . . . Often, but not alwa^^s, there is a close 

 correlation between display-flight and territory. The lark has the 

 spacious and illimitable]^skies\t his disposal and yet he is tethered by 

 an invisible bond to a patch of ground." 



The fact that Rougeot found the lyre-tail regularly in the same area 

 makes one wonder if there may not be some suggestion of site tenacity 

 or territoriality, even in a very loose sense, present here. Armstrong 

 observes that high-flying vocal or mechanical displays are most char- 



