| OCR Text |
Show 126 and plumbeous plumages, show rusty borders to the feathers of the upper parts, while besides the texture of their plumage leaves no doubt that they are very young birds in their first dress. Both adult and young exhibit the usual individual variation; tbe former varying in the greater or less bluish cast to the back and the bars underneath, the degree of blackness in the color of the pileuui, and the former exhibiting tints variously intermediate between the rufous and brown phases. There appears to be no well- marked sexual difference in plumage at any age, though the adult males seem to be rather more plumbeous than the females. The proper specific name for this species is involved in considerable doubt. Strickland is, we believe, the only one who has identified it with the Falco auperciliosits of Linnaeus; other authors having, for some reason, we know not what, discarded this name, and taken that of Falco tinus Latham, as the first designation of the species. So far as the original descriptions are concerned, both of those quoted are extremely inaccurate, and disagree in very important respects with the characters of the bird under consideration; but if there is no other clue to what species were meant by these authors than their diagnoses, Latham's description is much more inapplicable than that of Linmeus. It is as follows, the points of disagreement being italicized:- " F. pedibus flavis, corpore cinereo- fusco, subtus albido fasciis nigri-cantibus, vertice albido. Tiny Falcon, Lath. Synop. sup. p. 39. Habitat in Cayana; inter minimos numerandus; ab apice rostri ad basin cand. e uncias sex tantum implens." This is at best a very poor diagnosis of the species under consideration ; since, if this were the bird described, it is difficult to see why a bird which invariably has a uniform black or dusky vertex should have this portion described as white! Linnaeus describes his F. supcrciliosm as follows :- " F. cera pedibus palpebrisque luteis, corpore fusco albido undulato, remigibus ferrugineis uigrofasciatus. Habitat in Surinamo. Dahlberg. Magnitudo Piece. Corpus supra fuscum, subtus totum etiam femori-bus confertim nigro undulatum. Eemiges ferrugineae fasciis nigris plu-ribus; sed secundaria margine posteriore albido. Cauda nigra fasciis duabus latis & apice cinereis. Crissum album, strigis aliquot nigris. Uropygium albo nigroque rarium. Supercilia subtus nuda, prominula. Lora setis nigris patentibus. Eostrum & ungues nigri. Tectrices alarum inferiores albae lineolis tenuissimis nigris." This description is, in the main, a sufficiently accurate diagnosis of the present species in the transition- stage, or in moulting from the ferruginous plumage, which sometimes characterizes tbe young, into the adult plumbeous stage, remnants of the first dress being the ferruginous remiges, as described. But the clause " rump varied with black and white " is manifestly not a character of the present species, in which this part is uniform slaty, with, however, an indistinct white spotting beueath tbe surface, to be seen only upon disturbing the feathers. But this discrepancy is trifling compared with that in Latham's description of his Falco tinu8i and, unless there is a better reason than we know of, we cannot see why Linnaeus' name superciliosus should not be preferred. In case both these names be rejected on account of the reasons stated, Sparviu8 subniger Vieillot would be unobjectionable, since the type has been fully identified with this species by Pucheran. |
