The Descent of Man by Charles Darwin (books like harry potter TXT) 📕

[Fig. 37. The Ruff or Machetes pugnax (from Brehm’s ‘Thierleben’).]

The polygamous ruff (Machetes 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. The fowlers discover these spots by the turf being trampled somewhat bare. Here they fight very much like game- cocks, seizing each other with their beaks and striking with their wings. The great ruff of feathers round the 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 the case of birds of any structure serving as a shield. 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 when 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 provokes a general battle. (7. Macgillivray, ‘History of British Birds,’ vol. iv. 1852, pp. 177-181.) Of the pugnacity of web-footed birds, two instances will suffice: in Guiana “bloody fights occur during the breeding-season between the males of the wild musk-duck (Cairina moschata); and where these fights have occurred the river is covered for some distance with feathers.” (8. Sir R. Schomburgk, in ‘Journal of Royal Geographic Society,’ vol. xiii. 1843, p. 31.) Birds which seem ill-adapted for fighting engage in fierce conflicts; thus the stronger males of the pelican drive away the weaker ones, snapping with their huge beaks and giving heavy blows with their wings. Male snipe fight together, “tugging and pushing each other with their bills in the most curious manner imaginable.” Some few birds are believed never to fight; this is the case, according to Audubon, with one of the woodpeckers of the United States (Picu sauratus), although “the hens are followed by even half a dozen of their gay suitors.” (9. ‘Ornithological Biography,’ vol. i. p. 191. For pelicans and snipes, see vol. iii. pp. 138, 477.)

The males of many birds are larger than the females, and this no doubt is the result of the advantage gained by the larger and stronger males over their rivals during many generations. The difference in size between the two sexes is carried to an extreme point in several Australian species; thus the male musk-duck (Biziura), and the male Cincloramphus cruralis (allied to our pipits) are by measurement actually twice as large as their respective females. (10. Gould, ‘Handbook of Birds of Australia,’ vol. i. p. 395; vol. ii. p. 383.) With many other birds the females are larger than the males; and, as formerly remarked, the explanation often given, namely, that the females have most of the work in feeding their young, will not suffice. In some few cases, as we shall hereafter see, the females apparently have acquired their greater size and strength for the sake of conquering other females and obtaining possession of the males.

The males of many gallinaceous birds, especially of the polygamous kinds, are furnished with special weapons for fighting with their rivals, namely spurs, which can be used with fearful effect. It has been recorded by a trustworthy writer (11. Mr. Hewitt, in the ‘Poultry Book’ by Tegetmeier, 1866, p. 137.) that in Derbyshire a kite struck at a game-hen accompanied by her chickens, when the cock rushed to the rescue, and drove his spur right through the eye and skull of the aggressor. The spur was with difficulty drawn from the skull, and as the kite, though dead, retained his grasp, the two birds were firmly locked together; but the cock when disentangled was very little injured. The invincible courage of the game- cock is notorious: a gentleman who long ago witnessed the brutal scene, told me that a bird had both its legs broken by some accident in the cockpit, and the owner laid a wager that if the legs could be spliced so that the bird could stand upright, he would continue fighting. This was effected on the spot, and the bird fought with undaunted courage until he received his death-stroke. In Ceylon a closely allied, wild species, the Gallus Stanleyi, is known to fight desperately “in defence of his seraglio,” so that one of the combatants is frequently found dead. (12. Layard, ‘Annals and Magazine of Natural History,’ vol. xiv. 1854, p. 63.) An Indian partridge (Ortygornis gularis), the male of which is furnished with strong and sharp spurs, is so quarrelsome “that the scars of former fights disfigure the breast of almost every bird you kill.” (13. Jerdon, ‘Birds of India,’ vol. iii. p. 574.)

The males of almost all gallinaceous birds, even those which are not furnished with spurs, engage during the breeding-season in fierce conflicts. The Capercailzie and Black-cock (Tetrao urogallus and T. tetrix), which are both polygamists, have regular appointed places, where during many weeks they congregate in numbers to fight together and to display their charms before the females. Dr. W. Kovalevsky informs me that in Russia he has seen the snow all bloody on the arenas where the capercailzie have fought; and the black-cocks “make the feathers fly in every direction,” when several “engage in a battle royal.” The elder Brehm gives a curious account of the Balz, as the love-dances and love-songs of the Black-cock are called in Germany. The bird utters almost continuously the strangest noises: “he holds his tail up and spreads it out like a fan, he lifts up his head and neck with all the feathers erect, and stretches his wings from the body. Then he takes a few jumps in different directions, sometimes in a circle, and presses the under part of his beak so hard against the ground that the chin feathers are rubbed off. During these movements he beats his wings and turns round and round. The more ardent he grows the more lively he becomes, until at last the bird appears like a frantic creature.” At such times the black-cocks are so absorbed that they become almost blind and deaf, but less so than the capercailzie: hence bird after bird may be shot on the same spot, or even caught by the hand. After performing these antics the males begin to fight: and the same black-cock, in order to prove his strength over several antagonists, will visit in the course of one morning several Balz-places, which remain the same during successive years. (14. Brehm, ‘Thierleben,’ 1867, B. iv. s. 351. Some of the foregoing statements are taken from L. Lloyd, ‘The Game Birds of Sweden,’ etc., 1867, p. 79.)

The peacock with his long train appears more like a dandy than a warrior, but he sometimes engages in fierce contests: the Rev. W. Darwin Fox informs me that at some little distance from Chester two peacocks became so excited whilst fighting, that they flew over the whole city, still engaged, until they alighted on the top of St. John’s tower.

The spur, in those gallinaceous birds which are thus provided, is generally single; but Polyplectron (Fig. 51) has two or more on each leg; and one of the Blood-pheasants (Ithaginis cruentus) has been seen with five spurs. The spurs are generally confined to the male, being represented by mere knobs or rudiments in the female; but the females of the Java peacock (Pavo muticus) and, as I am informed by Mr. Blyth, of the small fire-backed pheasant (Euplocamus erythrophthalmus) possess spurs. In Galloperdix it is usual for the males to have two spurs, and for the females to have only one on each leg. (15. Jerdon, ‘Birds of India’: on Ithaginis, vol. iii. p. 523; on Galloperdix, p. 541.) Hence spurs may be considered as a masculine structure, which has been occasionally more or less transferred to the females. Like most other secondary sexual characters, the spurs are highly variable, both in number and development, in the same species.

[Fig.38. Palamedea cornuta (from Brehm), shewing the double wing-spurs, and the filament on the head.]

Various birds have spurs on their wings. But the Egyptian goose (Chenalopex aegyptiacus) has only “bare obtuse knobs,” and these probably shew us the first steps by which true spurs have been developed in other species. In the spur-winged goose, Plectropterus gambensis, the males have much larger spurs than the females; and they use them, as I am informed by Mr. Bartlett, in fighting together, so that, in this case, the wing-spurs serve as sexual weapons; but according to Livingstone, they are chiefly used in the defence of the young. The Palamedea (Fig. 38) is armed with a pair of spurs on each wing; and these are such formidable weapons that a single blow has been known to drive a dog howling away. But it does not appear that the spurs in this case, or in that of some of the spur-winged rails, are larger in the male than in the female. (16. For the Egyptian goose, see Macgillivray, ‘British Birds,’ vol. iv. p. 639. For Plectropterus, Livingstone’s ‘Travels,’ p. 254. For Palamedea, Brehm’s ‘Thierleben,’ B. iv. s. 740. See also on this bird Azara, ‘Voyages dans l’Amerique merid.’ tom. iv. 1809, pp. 179, 253.) In certain plovers, however, the wing-spurs must be considered as a sexual character. Thus in the male of our common peewit (Vanellus cristatus) the tubercle on the shoulder of the wing becomes more prominent during the breeding-season, and the males fight together. In some species of Lobivanellus a similar tubercle becomes developed during the breeding-season “into a short horny spur.” In the Australian L. lobatus both sexes have spurs, but these are much larger in the males than in the females. In an allied bird, the Hoplopterus armatus, the spurs do not increase in size during the breeding- season; but these birds have been seen in Egypt to fight together, in the same manner as our peewits, by turning suddenly in the air and striking sideways at each other, sometimes with fatal results. Thus also they drive away other enemies. (17. See, on our peewit, Mr. R. Carr in ‘Land and Water,’ Aug. 8th, 1868, p. 46. In regard to Lobivanellus, see Jerdon’s ‘Birds of India,’ vol. iii. p. 647, and Gould’s ‘Handbook of Birds of Australia,’ vol. ii. p. 220. For the Hoplopterus, see Mr. Allen in the ‘Ibis,’ vol. v. 1863, p. 156.)

The season of love is that of battle; but the males of some birds, as of the game-fowl and ruff, and even the young males of the wild turkey and grouse (18. Audubon, ‘Ornithological Biography,’