APPENDIX 



333 



Bush-Larks 



Fischer's Bush-Lark {Mirafra fischeri) is the thick-set, ruddy- 

 brown bird, with short tail and short rounded wings, that 

 makes the extraordinary vibrating noise already described 

 at p. 2-19. This was in thin bush-country at Sirnba, in 

 March ; but in its breeding-season in November, Commander 

 Lynes, R.N., tells me he heard and noticed it soaring quite 

 300 ft. in air with undulating flight, like that of a snipe 

 when "drumming" — but with this difference, that the 

 vibrant rattle was only produced when on the up-grade, 

 whereas snipe produce it only when dropping earthwards. 

 Even at that great height the rattle was clearly audible ; 

 indeed, at half-a-mile it sounded as distinct as when the 

 bird was close by. The annexed diagram shows the line 

 of flight. 



Starting from the ground at A, the bird mounts quickly to B. 



B to C — a few preliminary wing-beats. 



C to D— the " clapi^er " sound is produced. At D closes wings and 

 drops to E. 



E to F — preliminary wing-beats repeated. 



F to G — " clapper " repeated — and so on. 



Finally, Mirafra descends to half-way by a series of steep down-grades, 

 and completes remainder of descent to ground or bush by an almost 

 vertical drop of great rapidity. 



Duration of "clapper," three seconds ; of whole performance, three to 

 five minutes. 



Viewed from below, the outline of the bird on the wing resembles that 

 of a AVood-Lark, with rather large rounded wings, the inner secondaries 

 well clear of the body — thus allowing space for the requisite movement of 

 the wing over so large an arc (180°) which produces the sound {Lynes). 



