SEXUAL SELECTION 523 



it is to a large extent the external attractions of the male; 

 though no doubt his vigor, courage, and other mental 

 qualities come into play. We will begin with the indirect 

 evidence. 



Length of Courtship. — The lengthened period during 

 ■which both sexes of certain birds meet day after day at 

 an appointed place probably depends partly on the court- 

 ship being a prolonged affair, and partly on reiteration in 

 the act of pairing. Thus in Germany and Scandinavia the 

 balzing or leks of the black-cocks last from the middle of 

 March, all through April into May. As many as forty or 

 fifty, or even more, birds congregate at the leks; and the 

 same place is often frequented during successive years. 

 The lek of the capercailzie lasts from the end of March to 

 the middle or even end of May. In North America "the 

 partridge dances" of the Tetrao phasianellus "last for a 

 month or more." Other kinds of grouse, both in North 

 America and Eastern Siberia," follow nearly the same 

 habits. The fowlers discover the hillocks where the ruffs 

 congregate by the grass being trampled bare, and this shows 

 that the same spot is long frequented. The Indians of 

 Guiana are well acquainted with the cleared arenas, where 

 they expect to find the beautiful cocks of the Eock; aud 

 the natives of New Gruinea know the trees where from ten 

 to twenty male birds of paradise in full plumage congre- 

 gate. In this latter case -it is not expressly stated that the 

 females meet on the same trees, but the hunters, if not 

 specially asked, would probably not mention their presence, 

 as their skins are valueless. Small parties of an African 

 weaver {Ploceus) congregate, during the breeding season, 

 and perform for hours their graceful evolutions. Large 

 numbers of the Solitary snipe {Scolopax major) assemble 



' Nordman describes ("Bull. Soc. Imp. des Nat. Moscou," 1861, torn, 

 xxxiv. p. 264) the balzen of Tetrao v/rogaUoides in Amur Land. He estimated 

 the number of birds assembled at above a hundred, not counting the females, 

 which he hid in the surrounding bushes. The noises uttered differ from those 

 of T. urogalh». 



