5. Milvago megalopterus.
Aquila megaloptera, Meyen, Nov. Act. Acad. Cæs. Suppl. 1834, p. 64. Pl. VIII.
When ascending the Despoblado, a branch of the valley of Copiapó in Northern Chile, I saw several brown coloured hawks, which at the time appeared new to me, but of which I did not procure a specimen. These I have no doubt were the A. megaloptera of Meyen. In the British Museum there is a specimen, brought from Chile by Mr. Crawley. Mr. G. R. Gray suspects that this bird may eventually prove to be the young of the Phalcobænus montanus of D’Orbigny, and as I saw that bird (or another species having a close general resemblance with it) in the valleys of Northern Chile, although not in the immediate vicinity, this supposition is by no means improbable. Meyen’s figure at first sight appears very different from that of the young of the P. montanus, given by M. D’Orbigny, for in the latter the feathers over nearly the whole body are more distinctly bordered with a pale rufous shade, the thighs barred with the same, and the general tint is of a much redder brown. But with the exception of these differences, which are only in degree, I can find in M. D’Orbigny’s description no other distinguishing character, whilst on the other hand, there are numerous points of close resemblance between the two birds in the shadings, and even trifling marks of their plumage. Meyen, moreover, in describing the habits of his species, says, it frequents a region just below the limit of perpetual snow, and that it sometimes soars at a great height like a condor. Those which I saw had the general manners of a Polyborus or Milvago, and were flying from rock to rock amongst the mountains at a considerable elevation, but far below the snow-line. In these several respects, there is a close agreement with the habits of the P. montanus, as described by M. D’Orbigny. I will only add that the specimen in the British Museum appeared, independently of differences of plumage, distinct from the M. albogularis of Patagonia, from the thinness and greater prolongation of its beak, and the slenderness of its tarsi.
Sub-Fam.—BUTEONINÆ.
Craxirex. Gould.
Rostrum Buteonis sed longius; mandibulæ superioris margo rectus; versus apicem subitò incurvus. Alæ elongatæ. Cera lata. Nares ferè rotundæ, apertæ. Tarsi mediocres, anticè squamis tecti. Digiti magni, fortes; ungues obtusæ.
Mr. Gould was partly led to institute this genus from the facts communicated to him by me regarding the habits of the following species, which is found in the Galapagos Archipelago, and there supplies the place of the Polybori and Milvagines of the neighbouring continent of America. If a principle of classification founded on habits alone, were admissible, this bird, as will presently be shown, undoubtedly would be ranked with more propriety in the sub-family of Polyborinæ, than amongst the Buzzards. To the latter it is closely related in the form of its nostrils; in the kind of plumage which covers the head, breast, and shoulders; in the reticulation of the scales on its feet and tarsi, and less closely in the form of its beak. To the Polyborinæ it manifests an affinity in the great strength and length of its toes and claws, and in the bluntness of the latter; in the nakedness of the cere, in the perfectly uncovered nostrils, in the prolongation and bulk of the bill, in the straightness of the line of commissure, and in the narrow shape of the head. In these several respects, taken conjointly with its habits, this bird supplies a most interesting link in the chain of affinities, by which the true buzzards pass into the great American sub-family of carrion-feeding hawks. I am, indeed, unable to decide, whether I have judged rightly in placing this genus, as first of the Buteoninæ, instead of last of the Polyborinæ.
Birds. Pl. 2.
Craxirex Galapagoensis
Craxirex Galapagoensis. Gould.
Plate II.
Polyborus Galapagoensis. Proceedings of the Zoological Society for January, 1837, p. 9.
C. Mas. adult, Intensè fuscus; primariis nigris; secundariarum pogoniis internis transversim albo et fusco striatis; caudâ cinerascenti-fuscâ, transversim lineis angustis et numerosis intensè fuscis notatâ; rostro obscure corneo; pedibus olivaceo-flavis.
Long. tot. 20½ unc.; rostri, 1½; alæ, 15; caudæ, 8½; tarsi, 3¼.
Fæm. adult, fæminæ juniori ferè similis, pectore tamen fusco.
Fæm. juv. Capite corporeque intensè stramineis, fusco-variegatis; illo in pectore et abdomine prævalente; primariis fusco-nigris; rectricum pogoniis externè cinerascenti-fuscis, internè pallide rosaceis; utrisque lineis angustis et frequentibus fuscis transversim striatis, apicibus sordide albis; rostro nigrescenti-fusco; pedibus olivaceo-flavis.
Long. tot. 24 unc.; rostri, 1¾; alæ, 17¼; caudæ, 10½; tarsi, 3½.
Description of adult male.
Colour.—Entire dorsal aspect umber brown: base of feathers on hind part of neck, white; base of those on back, irregularly banded with pale fulvous, and the scapulars with a distinct band of it. The inferior feathers of upper tail coverts banded in like manner to their extremities. Tail dusky clove brown, obscurely marked with darkened transverse narrow bands. Primaries perfectly black towards their extremities, but with the outer edge of their base, gray: inner web banded and freckled with gray, brown, and white, which in the secondaries takes the form of regular bars. Under surface, entirely umber brown, but rather paler than the upper. Lining of wings gray, with irregular transverse brown bars: under-side of tail the same, but paler. Thighs of a rather yellower brown. Bill and cere horn colour, mottled with pale gray: tarsi yellow.
Form.—Beak, with apex much arched, both longer and more pointed than it is in the group of the Polyborinæ. Cere naked, with few bristles; nostrils large, quite uncovered, irregularly triangular, with the angles much rounded, and situated rather above a central line between the culmen and commissure. Fourth primary longest, but third and fifth nearly equal to it; first, four inches and a half shorter than fourth, and equal to the eighth; second shorter than fifth. Extremities of wing reaching within half an inch of end of tail. Tarsi strong, feathered for nearly a third of their length beneath the joint. Scales in narrow, undivided (with the exception in some instances of one) bands, covering the front of tarsus. Toes very strong and rather long, like those of the species of Milvago, and much more so than in the genus Buteo. Hind-toe equal in length to the inner one; but not placed quite so high on the Tarsus as in Polyborus. Basal joints of middle toe covered with small scales, with five large ones towards the extremity. Claws very strong, thick and long, and rather more arched, and broader than in Polyborus Brasiliensis; their extremities obtuse, but not in so great a degree as in some species of Milvago.
| Inches. | |
|---|---|
| Total length from tip of bill to end of tail following curvature of body | 20½ |
| Tail | 8½ |
| Wing, from elbow-joint to extremity of longest primary | 15 |
| Bill, from tip to anterior edge of eye measured in a straight line | ⁷⁄₁₀ |
| Tarsus, from soles of feet to centre of joint | 3½ |
| Hind claw from tip to root, measured in straight line | 1⅒ |
| Claw of middle toe | ⁹⁵⁄₁₀₀ |
Old female.
Colour.—Nearly as in young female, but with the breast dark brown.
Young female.
Colour.—Head, back of neck, back, wing coverts and tertiaries barred and mottled, both with pale umber brown (of the same tint as in the male bird) and with pale fulvous orange. On head and back of neck, each feather is of the latter colour, with a mere patch of the brown on its tip; but in the longer feathers, as in the scapulars, upper tail coverts, inner web and part of outer of the tertiaries, each is distinctly barred with the dark brown. Tail as in the old male. Primaries black as in male, with the inner webs nearly white, and marked with short transverse bars. Under surface and thighs of the same fulvous orange, but some of the feathers, especially those on the breast, are marked with small spots of umber brown on their tips. Some of the longer feathers on the flanks, on the under tail coverts, and on the linings of the wing, have irregular bars of the same.
Form and Size.—Larger and more robust than the male. Total length 24 inches. Tail ten and a half inches long, and therefore longer in proportion to the wings than in the other sex. Wings from joint to end of primaries, 17¼.
Habitat, Galapagos Archipelago, (October).
This bird is, I believe, confined to the Galapagos Archipelago, where on all the islands, it is excessively numerous. It inhabits, indifferently, either the dry sterile region near the coast, which, perhaps, is its most general resort, or the damp and wooded summits of the volcanic hills. This bird, in most of its habits and disposition, resembles the Milvago leucurus, or the Falco Novæ Zelandiæ of older authors. It is extremely tame, and frequents the neighbourhood of any building inhabited by man. When a tortoise is killed even in the midst of the woods, these birds immediately congregate in great numbers, and remain either seated on the ground, or on the branches of the stunted trees, patiently waiting to devour the intestines, and to pick the carapace clean, after the meat has been cut away. These birds will eat all kinds of offal thrown from the houses, and dead fish and marine productions cast up by the sea. They are said to kill young doves, and even chickens; and are very destructive to the little tortoises, as soon as they break through the shell. In these respects this bird shows its alliance with the buzzards. Its flight is neither elegant nor swift. On the ground it is able, like the M. leucurus and Phalcobænus montanus of D’Orbigny, to run very quickly. This habit which, as before observed, is so anomalous in the Falcons, manifests in a very striking manner the relation of this new genus with the Polyborinæ. It is, also, a noisy bird, and utters many different cries, one of which was so very like the shrill gentle scream of the M. chimango, that the officers of the “Beagle” generally called it either by this name, or from its larger size by that of Carrancha,—both names, however, plainly indicating its close and evident relationship with the birds of that family. The craw is feathered; and does not, I believe, protrude like that of the P. Brasiliensis or M. leucurus. It builds in trees, and the female was just beginning to lay in October. The bird of which the full figure has been given, is a young female, but of, at least, one year old. The old male bird is of a uniform dusky plumage, and is seen behind. The adult female resembles the young of the same sex, but the breast is dark brown like that of the male. In precisely the same manner as was remarked in the case of the M. leucurus, these old females are present in singularly few proportional numbers. One day at James’ Island, out of thirty birds, which I counted standing within a hundred yards of the tents, under which we were bivouacked, there was not a single one with the dark brown breast. From this circumstance I am led to conclude that the females of this species (as with the M. leucurus) acquire their full plumage late in life.