The Jacanas journey by very easy stages, frequently alighting to rest by the way; for they are so incapable of sustained flight that boys on the pampas occasionally take them, pursuing them on horseback till the birds drop down exhausted. I believe the migratory Rails travel in the same way—a matter not easily determined, as they migrate by night; but they are feeble-winged creatures, and when driven to rise flutter away as if wounded. I have observed the Jacanas migrating by day, but would not for this reason affirm that they do not journey by night, since the Bartram’s Sandpiper and other species journey both day and night.
The Jacana flies swiftly, in a straight line and close to the surface: the wings flutter rapidly; and there are frequent intervals of gliding. When rising it presents a most novel appearance, as the lovely pale green of the wings is quite concealed when the bird is at rest; the beauty of its flight is thus greatly enhanced by the sudden display of a hue so rare and delicate. At a distance from the beholder, and in a strong sunshine, the wings appear of a shining golden yellow. Not only when flying does the Jacana make a display of its beautiful wings; without rising it has a way of exhibiting them, appearing to delight as much in them as the Cockatoo does in its crest or the Peacock in its train. When several of these birds live in company, occasionally they all in one moment leave their feeding, and with quick excited notes, and clustering together in a close group, go through a singular and pretty performance, all together holding their wings outstretched and agitated, some with a rapid fluttering, others with a slow-moving leisurely motion like that of a butterfly sunning itself. The performance over, the birds peaceably scatter again. I have never observed Jacanas fighting.
Shortly after arriving they pair, and build a simple nest with few materials, usually on the floating weeds. The eggs are four, in shape like Snipe’s eggs, and have deep-brown spots on a pale yellowish-brown ground. During incubation the male keeps guard at some distance from the nest, and utters a warning cry at the approach of an intruder; the female instantly flies from the nest, but in rising renders herself very conspicuous. When the nest is approached the parent birds hover about, occasionally fluttering as if wounded, all the time keeping up a clamour of hurried angry notes somewhat resembling the barking cries of the Black-collared Stilt.
[ Fam. XLVII. CHARADRIIDÆ, or PLOVERS.]
Plovers are found all over the world’s surface and in every degree of latitude, and some of the species have an almost cosmopolitan distribution. In the Neotropical Region about twenty Plovers are known, of which seven are found within our limits. Three of these are Antarctic species that visit Argentina during the winter, one arrives in the opposite season from the north, and the other three are more or less abundant residents.
[386.] VANELLUS CAYENNENSIS (Gm.).
(CAYENNE LAPWING.)
Vanellus cayennensis, Burm. La-Plata Reise, ii. p. 502; Scl. et Salv. Nomencl. p. 142; iid. P. Z. S. 1868, p. 144 (Buenos Ayres); Durnford, Ibis, 1877, p. 42 (Chupat), p. 196; (Buenos Ayres), et 1878, p. 402 (Centr. Patagonia); Gibson, Ibis, 1880, p. 161 (Buenos Ayres); Barrows, Auk, 1884, p. 278 (Entrerios, Pampas); Seebohm, Plovers, p. 216. Philomachus cayanus, Darwin, Zool. Voy. ‘Beagle,’ iii. p. 127.
Description.—Wings with a large yellow spine. Above grey; broad front and thin vertical crest black; a patch on the scapulars bronzy purplish; upper tail-coverts white; primaries purplish black; greater coverts pure white, passing into greyish on the secondaries; lesser wing-coverts bronzy green; tail—basal half white, apical half purplish black tipped with white: beneath, chin, line down the middle of the throat and breast shining black; sides of neck grey, passing into white on the face; abdomen and under wing-coverts pure white; bill red, with black tip; feet flesh-colour: whole length 13·0 inches, wing 8·2, tail 4·2, tarsus 3·1. Female similar.
