Gen. Char. Body stout. Bill conical, very obsoletely notched, or smooth; somewhat compressed. Lower mandible not so deep as the upper. Commissure nearly straight. Gonys a little curved. Feet stout, not stretching beyond the tail; tarsus a little longer than the middle toe; outer toe a little longer than the inner; its claw not quite reaching to the base of the middle one. Hind toe appreciably longer than the middle one. Wings quite short and rounded, scarcely reaching beyond the base of the tail; the tertials considerably longer than the secondaries; the quills considerably graduated; the fourth longest; the first not longer than the tertials, and almost the shortest of the primaries. Tail moderately long, rather longer from coccyx than the wings, and considerably graduated; the feathers oval at the tips, and not stiffened. Crown and back similar in color, and streaked; beneath thickly streaked, except in M. palustris. Tail immaculate. Usually nest on ground; nests strongly woven of grasses and fibrous stems; eggs marked with rusty-brown and purple on a ground of a clay color.
Melospiza melodia.
This genus differs from Zonotrichia in the shorter, more graduated tail, rather longer hind toe, much more rounded wing, which is shorter; the tertiaries longer; the first quill almost the shortest, and not longer than the tertials. The under parts are spotted; the crown streaked, and like the back.
There are few species of American birds that have caused more perplexity to the ornithologist than the group of which Melospiza melodia is the type. Spread
over the whole of North America, and familiar to every one, we find each region to possess a special form (to which a specific name has been given), and yet these passing into each other by such insensible gradations as to render it quite impossible to define them as species. Between M. melodia of the Atlantic States and M. insignis of Kodiak the difference seems wide; but the connecting links in the intermediate regions bridge this over so completely that, with a series of hundreds of specimens before us, we abandon the attempt at specific separation, and unite into one no less than eight species previously recognized.
Taking, then, the common Song Sparrow of the Eastern Atlantic States (M. melodia) as the starting-point, and proceeding westward, we find quite a decided difference (in a variety fallax) when we reach the Middle Province, or that of the Rocky Mountains. The general tints are paler, grayer, and less rusty; the superciliary stripe anteriorly more ashy; the bill, and especially the legs, more dusky, the latter not at all to be called yellow. The bill is perhaps smaller and, though sometimes equal to the average of eastern specimens, more slender in proportion. In some specimens (typical fallax) the streaks are uniform rufous without darker centres,—a feature I have not noticed in eastern melodia. Another stage (heermanni) is seen when we reach the Pacific coast of California, in a darker brown color (but not rufous). Here the bill is rather larger than in var. fallax, and the legs colored more like typical melodia. In fact, the bird is like melodia, but darker. The stripes on the back continue well defined and distinct. M. samuelis (=gouldi) may stand as a smaller race of this variety.
Proceeding northward along the Pacific coast, another form (var. guttata), peculiar to the coast of California, is met with towards and beyond the mouth of the Columbia (coming into Southern California in winter). This is darker in color, more rufous; the stripes quite indistinct above, in fact, more or less obsolete, and none, either above or below, with darker or blackish centres. The sides, crissum, and tibia are washed with ochraceous-brown, the latter perhaps darkest. The bill is proportionally longer and more slender. This race becomes still darker northward, until at Sitka (var. rufina) it shows no rufous tints, but a dusky olive-brown instead, including the streaks of the under parts. The markings of the head and back are appreciable, though not distinct. The size has become considerably larger than in eastern melodia, the average length of wing being 3.00, instead of 2.60.
The last extreme of difference from typical melodia of the east is seen in the variety insignis from Kodiak. Here the size is very large: length, 7.00; extent, 10.75; wing, 3.20. The bill is very long (.73 from forehead), the color still darker brown and more uniform above; the median light stripe of vertex scarcely appreciable in some specimens; the superciliary scarcely showing, except as a whitish spot anteriorly. The bill and feet have become almost black.
The following synopsis may serve as a means by which to distinguish the several races of this species, as also the two remaining positive species of the genus:—