1911 Encyclopædia Britannica/Screamer
SCREAMER, a bird inhabiting Guiana and the Amazon valley, so called in 1781 by T. Pennant (Gen. Birds, p. 37) “from the violent noise it makes”—the Palamedea cornuta of Linnaeus. First made known in 1648 by G. de L. Marcgrav under the name of “Anhima,” it was more fully described and better figured by Buffon under that of Kamichi, still applied to it by French writers. Of about the size of a turkey, it is remarkable for the curious “horn” or slender caruncle, more than three inches long, it bears on its crown, the two sharp spurs with which each wing is armed, and its elongated toes. Its plumage is plain in colour, being of an almost uniform greyish black above, the space round the eyes and a ring round the neck being variegated with white, and a patch of pale rufous appearing above the carpal joint, while the lower parts of the body are white. Closely related to this bird is another first described by Linnaeus as a species of Parra (see Jaçaná), to which group it certainly does not belong, but separated therefrom by Illiger to form the genus Chauna, and now known as C. chavaria, very generally in English as the “Crested Screamer,” a name which was first bestowed on the Seriema (q.v.). This bird inhabits the lagoons and swamps of Paraguay and Southern Brazil, where it is called “Chajá” or “Chaka,” and is smaller than the preceding, wanting its “horn,” but having its head furnished with a dependent crest of feathers; while the plumage is grey. Its nest is a light construction of dry rushes, having its foundation in the water, and contains as many as six eggs, which are white tinged with buff. The young are covered with down of a yellowish-brown colour. A most singular habit possessed by this bird is that of rising in the air and soaring there in circles at an immense altitude, uttering at intervals the very loud cry of which its local name is an imitation. From a dozen to a score may be seen at once so occupying themselves. The young are often taken from the nest and reared by the people to attend upon and defend their poultry, a duty which is faithfully[1] and, owing to the spurs with which the chaka’s wings are armed, successfully discharged. Another very curious property of this bird, which was observed by Jacquin, who brought it to the notice of Linnaeus,[2] is its emphysematous condition—there being a layer of air-cells between the skin and the muscles, so that on any part of the body being pressed a crackling sound is heard. In Central America occurs another species, C. derbiana, chiefly distinguished by the darker colour of its plumage. For this a distinct genus, Ischyrornis, was proposed, but apparently without necessity, by A. B. Reichenbach (Syst. Avium. p. xxi.).
The taxonomic position of the Palamedeidae, for all will allow to the screamers the rank of a family at least, has been much debated. Their anserine relations were pointed out by W. K. Parker in the Zoological Proceedings for 1863 (pp. 511-518, and in the same work for 1867 T. H. Huxley placed the family among his Chenomorphae; but this view was contravened in 1876 by A. H. Garrod, who said, “The screamers must have sprung from the primary avian stock as an independent offshoot at much the same time as did most of the other important families.” P. L. Sclater in 1880 placed them in a distinct order, Palamedeae, which he, however, placed next to the true Anseres, and they are now generally regarded as forming a suborder of anseriform birds.