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Show 20 ZOOLOGY OF TilE VOYAGE OF TilE BEAGLE. · en by M D'Orbigny. Although the main difference beP. montlantts, gbt~ ds l·s th~ colour of their breasts, yet it must be observed, tween t 1e two Ir ' • . . · · · h that in the JJf. albogula1·is there is some mdiCatwn of an, mc~p1ent c ange from white to brown in the plumage of that part. But as fM. h~ Ohrbhignhy1 w~o was acquam· t ed w1' th the young birds of the P. mo.n t.a nu.s , (o. w. 1c e as g1ven a fi ) does not mention so remarkable a mod1ficatwn m Its plumage, as must tagkuere p'l ace on the supposition of JJ!. albogularz·s be·m ~ an 1· mmatur_e b1' r d of t h at species; and as the geographical range of the two IS ~o very different, I am induced to consider them distinct. Moreover, on the plams of Santa Cruz, I saw several birds, and they appeared to me similar in their colouring. TheM. albogulat ·is is remarkable from the confined locality which it appears to frequent. A few pair were seen during the ascent of the river Sa~ta Cruz, (Lat. 50° S.) to the C~rdillera · but not one individual was observed m any other part of Patagoma. They a~peared to me to resemble, in their gait a~d m~nner. of flight, the P. Brasiliensis. but they were rather wilder. They hved m pa1rs, and generaJly were near th'e river. One day I observed a couple standing with the Carranchas and M. pezoporus, at a short distance from the carcass of a guanaco, on which the condors had commenced an attack. These peculiarities of habit are described by M. D'Orbigny in almost the same words, as occurring with the P. montanus; both birds frequent desert countries; the P. montanus, however, haunts the great mountains of Bolivia, and this species, the open plains of Patagonia. In the valleys north of 30° in Chile, I saw several pair, either of this species, or of the P. montanus of D'Orbigny, (if, as is probable, they are different) or of some third kind. From the circumstance of its not extending (as I believe) so far south even as the valley of Coquimbo, it is extremely improbable that it should be theM. albogularis,-an inhabitant of a plain country twenty degrees further south. On the other hand, the P. rnontanus lives at a great elevation on the mountains of Upper Peru; and therefore it is probable that it might be found in a higher latitude, but at a less elevation. M. D'Orbigny says, "Elle aime les terrains sees et depourvus de grands vegetaux, qui lui seraient inutiles; car il nous est prouve qu'elle ne se perche pas sur les branches." In another part he adds, " Elle descend cependant quelq uefois jusque pres de la mer, sur la c<>te du Perou, mais ce n'est que pour peu de temps, et peut~ tre afin d'y chercher momentanement une nourriture qui lui manque dans son sejour habituel; peut-~tre aussi la nature du sol l'y attire-t-elle; car elle y trouve les terrains a rides qui lui sont propres." * This is so entirely the character of the northern parts of Chile, that, it appears to me extremely probable, that the P. montanus, which inhabits the great mountains of Bolivia, descends, in Northern Chile, to near the shores of the Pacific; but that further * Voyage dans !'Amerique Meridionale Partie, Oiscaux, p. 52. BIRDS. 21 south, and on the opposite side of the Cordillera, it is replaced by an allied species,--the M. albogulaTis of Santa Cruz. 6. MILVAGO MEGALOPTERUS. Aquila megaloptcra, Meven, Nov. Act. Acad. Cree. Suppl. 1834, p. 04. Pl. VIII. When ascending the Despoblado, a branch of the valley of Copiap6 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 Pltalcobamus rnontanus 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 yicinity, 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 Polybm·us 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 cl~se 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. albogulaTis of Patagonia, from the thinness and greater prolongation of its beak, and the slenderness of its tarsi. |