| OCR Text |
Show 1904.] TWO SPECIMENS OF HYBRID GROUSE. 413 represented by white ones of the same kind, which become more conspicuous through contrast with the black than the brown is in the Blackcock. On the rump of the Riporre, however, the brown of the feathers is substituted by white only at their edges, while otherwise the fine wavy brownish lines remain. The upper tail-coverts are black but have broad white edges, and so have, although to a less extent, the middle rectrices. In the latter the white edges are exaggerations of the conditions found in the immature Blackcock; in the former the white edges correspond to the freckled edges of the same feathers in the Blackcock. The tail of the Riporre is deeply cleft, so that the middle rectrices are 2|-3| cm. shorter than the outer. The wing-coverts look almost all white, but a closer examination reveals that their basal hidden parts are black, or at least densely sprinkled with blackish. The white in these feathers has a distribution which corresponds to the area of the same feathers of the Blackcock, which is freckled with buff. The ends of the secondaries of the Rippore are more broadly tipped with white than in the Blackcock. But otherwise these parts are blackish, richly mottled with white all over their middle and basal portion. This is the more peculiar, as these parts of the secondaries are pure white in the Blackcock as well as in the Willow-Grouse. Here is thus a characteristic which is not inherited from either of the parents as it appears at first, but it is nevertheless a tetricid characteristic. The secondaries of the Blackcock are, between the white basal half and the terminal narrow white edge, blackish, more or less mottled with buff. This area has, in the Riporre, expanded over the greater basal part of the feathers at the same time as the mottling became white instead of buff. In such a way the Riporre lost the, for the Blackcock, characteristic broad white band across the wing, while the narrow terminal band became broadened. The outer web of the primaries, which in the Blackcock is pale brownish with whitish mottling, has in the Riporre become wholly white, and the inner web has in the latter become mottled with white and quite white at the tips, where the Blackcock shows a mottled area. A broad band through the eye of the Riporre is white. In the same place the immature Blackcock, or that in summer plumage, is mottled with white. Below this space the Riporre has a black band in which the feathers are very feebly edged with white. The same area is in the Blackcock glossy bluish black, but immature males often show the same whitish edging. although still less developed. The fore-neck and the sides of the neck, as well as the chest and belly, of the Riporre are white, although the invisible basal parts of the feathers are more or less black. The upper part of the breast is black, but mixed with broadly white-edged feathers. The feathers of the flanks are black, with broad edges or outer halves white, whereby a spotted appearance is produced. The lower parts have thus received more white from the Willow-Grouse than the upper parts have. |
