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.)
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