62 
SEXUAL SELECTION: BIRDS. 
Part 
back, according to Mr. R. Haymond, and not, ,u 
Audubon thought, by striking them against his sid eS ' 
The sound thus produced is compared by some t£ 
distant thunder, and by others to the quick roll of 11 
drum. The female never drums, “ but flies directly t0 
“ the place where the male is thus engaged.” In tb® 
Himalayas the male of the Kalij-pheasant “ often mak ® 8 
“ a singular dramming noise with his wings, not unlik® 
“ the sound produced by shaking a stiff piece of cloth- 
On the west coast of Africa the little black-weavef* 
(Ploceus?) congregate in a small party on the bush l> - 
round a small open space, and sing and glide through 
the air with quivering wings, “ which make a rap 1 ' 1 
“ whirring sound like a child’s rattle.” One bird al't< ?l 
another thus performs for hours together, but only duriPr 
the courting-season. At this same season the males ot 
certain night-jars (Caprimulgus) make a most strung® 
noise with their wings. The various species of wood 
peckers strike a sonorous branch with their beaks, wit 1 
so rapid a vibratory movement that “the head appea 1 *’ 
“ to be in two places at once.” The sound thus pr° 
duced is audible at a considerable distance, but can 
not be described; and I feel sure that its cause wotu ( 
never be conjectured by any one who heard it for tb' 
first time. As this jarring sound is made chiefly duttDe 
the breeding-season, it has been considered as a loV® 
song; but it is perhaps more strictly a love-call. lb® 
female, when driven from her nest, has been observe 
thus to call her mate, who answered in the sa# 1 ® 
manner and soon appeared. Lastly the male Hoop 0 ® 
(Upupa epops) combines vocal and instrumental musk > 
for during the breeding-season this bird, as Mr. Swinh°® 
saw, first draw's in air and then taps the end of 
beak perpendicularly down against a stone or the truf* v 
of a tree, “ when the breath being forced down tb® 
