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Show 40 SEXUAL SELECTION : BIRDS. PAil'l' If. am assured by Mr. J. J cnner vVeir that . the. birdcatchers can distinguish the males by their slightly longer beaks. The flocks of males, as an old and trustworthy bird-catcher asserted, are commonly fo~ncl feedinfl' on the seeds of the teazle (Dipsacus) wluch they ca~ reach with their elongated beaks, whilst the fcmaleH more commonly feed on the seeds of the b:tony or Scrophularia. \Vith a slight difference of this nature as a foundation, we can sec how the beaks of the two· s xes might be made to differ greatly through .natur~l selection. In all these cases, however, especmlly m that of the quarrelsome humming-birds, it is possible that the differences in the beaks may have been first acquired by the males in relation to ~heir ~attles, and afterwards led to slightly changed habits of ltfe. Law of Battle.-Almost all n:ale birds are extrem~ly PuO'nacious, usiuo- their beaks, Wings, and legs for fightwg tog0e ther. V\ b . l b' l 7 e see this every spring w1t 1 our ro ms anc sparrows. The smallest of all birds, namely the humminD"- bird, is one of the most quarrelsome. Mr. G osso :.~ desc~ibes a battle, in which a pair of humming-birdsseized hold of each other's beaks, anrl whirled round nnd ronnel, till they almost fell to the ground; and M. Montes de Oca, in speaking of another genus, says that two males rarely meet without a fierce aerial encounter: when kept in cages "their fighting bas mostly en~ed " in the splittinO' of the tongue of one of the two, whJCh "then surely dles from being unable to feed." 4 \Vith Waders, the males of the common water-hen (Gallinula chloropus) "when pairing, fight violently for tho females: " they stand nearly upright in the water and strike " with their feet." 'rwo were seen to be thus engaged 3 Quoted by l\ir. Gould, 'Introduction to the'l'rochilidoo,' 18G1, p. 20 •. • Gould, ibid. p. 52. CH.u. Xlll. LAW OF BATTLE. 41 for half an hour, until one got hold of the head of the other which would have been killed, had not the observ~ r interfered ; the female all the time looking on as a qmet spectator.:> The males of an allied bird (Gallicre. t cristatus), as 1\-Ir. Blyth informs me, are one third larger than the females, and are so pugnacious during the breeding-season, that they are kept by the natives of Eastern Bengal for the sake of fighting. Various other birr1s are kept in India for the same purpose, for instance the Bulbuls (Pycnonot~ts luemorrho~ts) which "fight with great spirit." 6 The polygamous Ruff (lliachetes pugnax, fig. 37) is notorious for his extreme pugnacity; and in the spring, the males, which are considerably larger than the females, congregate day after day at a particular spot, where the females propose to lay their eggs. 'rhe fowlers discover these spots by the turf being trampled somewhat bare. Here they fight very much like gamecocl.: s, seizin~· each other with their beaks and strikin()' with their wings. ~rhe great ruff of feathers round th: neck is then erected, and according to Col. Montagu " sweeps the ground as a shield to defend the more "tender parts;" and this is the only instance known to me in th~ case of birds, of any structure serving as a ~hield. The. ruff of feathers, however, from its varied and rich colours probably serves in chief part as an ornament. Like most pugnacious birds, they seem always ready to fight, and wheu closely confined often kill each other; but Montagu observed that their pugnacity becomes greater during the spring, when the long feathers on their necks are fully developed; and at this period the least movement by any one bird 6 W. Tl10mpson, 'Nat. llist. of Irolnnd: Birds,' vol. ii. 1850, p. S27 u Jcrdon, 'Birds of India,' 1863, vol. ii. p. 96. |