Female in Summer. Plate CCCLXVIII. Fig. 3.
The female does not differ materially from the male, the yellow bands being only broader and lighter.
Very great differences are observed in the length and form of the claws, they being in some individuals very long, thin-edged, and tapering, to a rounded point; in others very short, being worn down to the stump. This species is considerably smaller than the Ptarmigan of Scotland, which it precisely resembles in its winter plumage. In its summer plumage, however, it differs in having the markings larger; and as yet no specimens have been obtained marked with undulated slender, ash-grey, and dusky lines, in any degree approaching those characteristic of the British bird in its autumnal plumage. The bill of the Rock Grous is shorter and thicker than that of the Ptarmigan, although the reverse has been alleged.
MOUNTAIN MOCKING BIRD.
Turdus montanus.
PLATE CCCLXIX. Male.
This interesting and hitherto unfigured species was procured on the Rocky Mountains by Dr Townsend, who forwarded a single specimen to Philadelphia, where I made a drawing of it. The following notice by Mr Nuttall shews that it is nearly allied in its habits to the Mocking Bird:—
“On the arid plains of the central table-land, betwixt the northern sources of the Platte and the Colorado of the West, in the month of June, we frequently heard the cheering song of this delightful species, whose notes considerably resemble those of the Brown Thrush, with some of the imitative powers of the Mocking Bird. For a great part of the day, and especially early and late, its song resounds through the desert plains, as it warbles to its mate from some tall weed or bush of wormwood, and continues with little interruption nearly for an hour at a time. We met with it in the plains exclusively, till our arrival at Wallah Wallah, but we are not certain of having seen it in any part of California, it being apparently entirely confined to the cooler and open regions of the Rocky Mountains. Just before arriving at Sandy Creek of the Colorado, while resting for refreshment at noon, I had the good fortune to find the nest in a wormwood bush, on the margin of a ravine, from whence the male was singing with its unusual energy. It contained four almost emerald green eggs, spotted with dark olive of two shades, more numerous towards the greater end, the spots large and roundish. The nest itself was made of small twigs and rough stalks, lined with stripes of bark and bison wool. The female flew off to a little distance, and looked on her unwelcome and unexpected visitor, without uttering either call or complaint.”
Orpheus montanus, Mountain Mocking Bird, Townsend, Journal of Acad. of Nat. Sciences of Philadelphia, vol. vii. p. 192.
Adult Male. Plate CCCLXIX. Fig. 1.
Bill of moderate length, rather slender, compressed, straightish, pointed; upper mandible with the dorsal line slightly declinato-arcuate, the sides convex toward the end, the edges sharp, with a slight sinus close to the narrow declinate tip; lower mandible with the angle short and narrow, the dorsal line straight, the edges sharp and a little declinate at the end, the tip narrow; the gape-line very slightly arched.