1902 Encyclopedia > Goatsucker

Goatsucker




GOATSUCKER, a bird from very ancient times absurdly believed to have the habit implied by the common name it bears in many European tongues besides our own-as testified by the Greek Alyo6r)\a<;, the Latin Capri-mulgus, Italian Succiacapre, Spanish Chotacabras, French Tettechèvre, and German Ziegenmelker. The common Goatsucker (Caprirnulgus europceus, Linn.), is admittedly the type of a very peculiar and distinct Family Caprimul-gidce, a group remarkable for the flat head, enormously wide mouth, large eyes, and soft, pencilled plumage of its members, which vary in size from a Lark to a Crow. Its position has been variously assigned by systematists. Though of late years judiciously removed from the Passeres, in which Linnajus placed all the species known to him, Professor Huxley considers it to form, with two other Families—the Swifts (Cypselidce) and Humming-birds (Trochilidce), the division Cypselomorphce of his larger group jEgithognathce, which is equivalent in the main to the Linnseau Passeres There are two ways of regarding the Caprimidgidce—one including the genus Podargus and its allies, the other recognizing them as a distinct Family, Podargidce. As a matter of convenience we shall here comprehend these last in the Caprimidgidce, which will then contain two subfamilies, Caprimulgince and Podar-ginm ; for what, according to older authors, constitutes a third, though represented only by Sleatornis, the singular

Common Goatsucker.
Oil-bird, or Guacharo, certainly seems to require separation as an independent Family (see GUACHARO).

Some of the differences between the Caprimulgince and Podargincs have been pointed out by Mr Sclater (Proc. Zool. Soc, 1866, p. 123), and are very obvious. In the former, the outer toes have four phalanges only, thus presenting a very uncommon character among birds, and the middle claws are pectinated; while in the latter the normal number of five phalanges is found, and the claws are smooth, and other distinctions more recondite have also been indicated by him (loin, cit., p. 582). The Caprimulgince may be further divided into those having the gape thickly beset by strong bristles, and those in which there are few such bristles or none—the former containing the genera Capri-mulgus, Antrostomus, Nyctidromus, and others, and the latter Podager, Chordiles, Lyncornis, and a few more.

The common Goatsucker of Europe (C eurojiceus) arrives late in spring from its winter retreat in Africa, and its presence is soon made known to us by its habit of chasing its prey, consisting chiefly of moths and cockchafers, in the even-ing-twilight. As the season advances the song of the cock, from its singularity, attracts attention amid all rural sounds. This song seems to be always uttered when the bird is at rest, though the contrary has been asserted, and is the con-tinuous repetition of a single burring note, as of a thin lath fixed at one end and in a state of vibration at the other, and loud enough to reach in still weather a distance of half-a-mile or more. On the wing, while toying with its mate, or performing its rapid evolutions round the trees where it finds its food, it has the habit of occasionally producing another and equally extraordinary sound, sudden and short, but somewhat resembling that made by swinging a thong in the air, though whether this noise proceeds from its mouth is not ascertained. In general its flight is silent, but at times when disturbed from its repose, its wings may be heard to smite together. The Goatsucker, or, to use per-haps its commoner English name, Nightjar, passes the day in slumber, crouching on the ground or perching on a tree —in the latter case sitting not across the branch but length-ways, with its head lower than its body. In hot weather, however, its song may sometimes be heard by day and even at noontide, but it is then uttered, as it were,, drowsily, and without the vigour that characterizes its crepuscular or nocturnal performance. Towards evening the bird becomes active, and it seems to pursue its prey throughout the night uninterruptedly, or only occasionally pausing for a few seconds to alight on a bare spot—a pathway or road— and then resuming its career. It is one of the few birds that absolutely make no nest, but lays its pair of beautifully-marbled eggs on the ground, generally where the herbage is short, and often actually on the soil. So light is it that the act of brooding, even where there is some vegetable growth, produces no visible depression of the grass, moss, or lichens on which the eggs rest, and the finest sand equally fails to exhibit a trace of the parental act. Yet scarcely any bird shows greater local attachment, and the precise site chosen one year is almost certain to be occupied the next. The young, covered when hatched with dark-spotted down, are not easily found, nor are they more easily discovered on becoming fledged, for their plumage almost entirely resembles that of the adults, being a mixture of reddish-brown, grey, and black, blended and mottled in a manner that passes description. They soon attain their full size and power of flight, and then take to the same manner of life as their parents. In autumn all leave their summer haunts for the south, but the exact time of their departure has hardly been ascertained. The habits of the Nightjar, as thus described, seem to be more or less essen-tially those of the whole Subfamily—the differences obser-vable being apparently less than are found in other groups of birds of similar extent.





A second species of Goatsucker (C. ruficollis), which is somewhat larger, and has the neck distinctly marked with rufous, is a summer visitant to the south-western parts of Europe, and especially to Spain and Portugal. The occur, rence of a single example of this bird at Killingworth, near Newcastle-on-Tyne, in October 1856, has been re-corded by Mr Hancock (Ibis, 1862, p. 39); but the season of its appearance argues the probability of its being but a casual straggler from its proper home. Many other species of Caprirnulgus inhabit Africa, Asia, and their islands, while one (C. macrurus) is found in Australia. Very nearly allied to this genus is Antrostonus, an American group containing many species, of which the Cbuck-wuTs-widow (A. carolinensis) and the Whip-poor-will (A. voci-ferus) of the eastern United States (the latter also reaching Canada) are familiar examples. Both these birds take their common name from the cry they utter, and their habits seem to be almost identical with those of the Old-World Goatsuckers. Passing over some other forms which need not here be mentioned, the genus Nyctidromus, though consisting of only one species (E. albicollis) which inhabits Central and part of South America, requires re-mark, since it has tarsi of sufficient length to enable it to run swiftly on the ground, while the legs of most birds of the Family are so short that they can make but a shuffling progress. Beleothreptes, with the unique form of wing possessed by the male, needs mention. Notice must also be taken of two African species, referred by some ornithologists to as many genera (Macvodipteryx and Cos-metornis), though probably one genus would suffice for both. The males of each of them are characterized by the wonderful development of the ninth primary in either wing, which reaches in fully adult specimens the extraordinary length of 17 inches or more. The former of these birds, the C. macrodipterus of Afzelius, is considered to belong to the west coast of Africa, and the shaft of the elongated remiges is bare for the greater part of its length, retaining the web, in a spatulate form, only near the tip. The latter, to which the specific name of vexillarius was given by Mr Gould, has been found, on the east coast of that continent, and is reported to have occurred in Madagascar and Socotra. In this the remigial streamers do not lose their barbs, and as a few of the next quills are also to some extent elongated, the bird, when flying, is said to look as though it had four wings. Specimens of both are rare in collections, and no traveller seems to have had the opportunity of studying the habits of either so as to suggest a reason for this marvellous sexual development.

The second group of Caprimulgince, those which are but poorly or not at all furnished with rictal bristles, contains about five genera, of which there is here only room to par-ticularize Lyncornis of the Old World and Chordiles of the New. The species of the former are remarkable for the tuft of feathers which springs from each side of the head, above and behind the ears, so as to give the bird an appear-ance like some of the " Horned " Owls—those of the genus Scops, for example; and remarkable as it is to find certain forms of two Families, so distinct as are the Slrigidce and the Caprimulgidce, resembling each other in this singular external feature, it is yet more remarkable to note that in some groups of the latter, as in some of the former, a very curious kind of dimorphism takes place. In either case this has been frequently asserted to be sexual, but on that point doubt may fairly be entertained. Certain it is that in some groups of Goatsuckers, as in some groups of Owls, indivi-duals of the same species are found in plumage of two entirely different hues—rufous and grey, Tbe only ex-planation as yet offered of this fact is that the difference is sexual, but, as just hinted, evidence to that effect is con-flicting. It must not, however, be supposed that this com-mon feature, any more than that of the existence of tufted forms in each group, indicates any close relationship between them. The resemblances may be due to the same causes, concerning which future observers may possibly enlighten us, but at present we must regard them as analo-gies not homologies The species of Lyncornis inhabit the Malay Archipelago, one, however, occurring also in China. Of Chordiles the best known species is the Night-hawk of North America (C. virginianus or C. popetue), which has a wide range from Canada to Brazil. Others are found in the Antilles and in South America. The general habits of all these birds agree with those of the typical Goatsuckers.

We have next to consider the birds forming the genus Podargus and those allied to it, whether they be regarded as a distinct Family, or as a Subfamily of Caprimulgidce. As above stated, they have feet constructed as those of birds normally are, and their sternum seems to present the con-stant though comparatively trivial difference of having its posterior margin elongated into two pairs of processes, while only one pair is found in the true Goatsuckers. Podargus includes the bird (P. cuvleri) known from its cry as Morepork to Tasmanian colonists, and several other species, the number of which is doubtful, from Australia and New Guinea. They have comparatively powerful bills, and it would seem feed to some extent on fruits and berries, though they mainly subsist on insects, chiefly Cicadce and Phasmidce. They also differ from the true Goatsuckers in having the outer toes partially reversible, and they are said to build a flat nest on the horizontal branch of a tree for the reception of their eggs, which are of a spotless white. Apparently allied to Podargus, but differing among other respects in its mode of nidification, is JEgotheles, which belongs also to the Australian Subregion ; and further to the northward, extending throughout the Malay Archipelago and into India, comes Batrachoslomus, wherein we again meet with species having aural tufts somewhat like Lyncornis. The Podargince are thought by some to be represented in the New World by the genus Nyclibius, of which several species occur from the Antilles and Central America to Brazil. Finally, it maybe stated that none of the Caprimulgidce seem to occur in Polynesia or in New Zealand, though there is scarcely any other part of the world suited to their habits in which members of the Family are not found, (A. N.)







Search the Encyclopedia:



About this EncyclopediaTop ContributorsAll ContributorsToday in History
Sitemaps
Terms of UsePrivacyContact Us



© 2005-17 1902 Encyclopedia. All Rights Reserved.

This website is the free online Encyclopedia Britannica (9th Edition and 10th Edition) with added expert translations and commentaries