The young when fledged have the bill and claws black, the cere and feet dull yellow; the upper parts brownish-grey, the scapulars and quills tipped with white, the former also margined, with yellowish-brown; the primary and secondary coverts are also tipped with white; the smaller wing-coverts are brownish-black; the outer webs of all the tail-feathers are more or less brownish-grey toward the end. The lower parts are white, the feathers on the breast tinged with brownish-yellow at the end, and with the shaft yellowish-brown. The lower wing-coverts are all white. CHESTNUT-BACKED TITMOUSE. _PARUS RUFESCENS_, TOWNSEND. PLATE CCCLIII. MALE AND FEMALE. You have before you on the same plate three species of _Parus_, two of which are new to science. Of specimens of these I obtained possession in consequence of the purchase which I made of part of Dr TOWNSEND’s hard-earned collection, made during his laborious expedition over the Rocky Mountains, and the valley of the Columbia River. For an account of the habits of those which are not found to the east of the Rocky Mountains, I am indebted to my friends THOMAS NUTTALL, Esq., and J. K. TOWNSEND, M. D. Mr NUTTALL’s notice respecting the present species is as follows:— “The Chestnut-backed Titmouse is seen throughout the year in the forests of the Columbia, and as far south as Upper California, in all which tract it breeds, forming, as I have some reason to believe, a pendulous, or at least an exposed nest, like some of the European species. It is made of large quantities of hypna and lichens, and copiously and coarsely lined with deer’s hair and large feathers, such as those of the Grouse and the Jay. They are commonly seen in small flocks of all ages in the autumn and winter, when they move about briskly, and emit a number of feeble querulous notes, after the manner of the Chickadee, or common species, _Parus atricapillus_, but seldom utter any thing like a song, though now and then, as they glean about, they utter a _t’she_, _de_, _de_, or _t’dee_, _t’dee_, _dee_, their more common querulous call, however, being like _t’she_, _dé_, _de_, _vait_, _t’she_, _de_, _de_, _vait_, sometimes also a confused warbling chatter. The busy troop, accompanied often by the common species, the _Regulus tricolor_, and the small yellow-bellied _Parus_, are seen flitting through bushes and thickets, carefully gleaning insects and larvæ for an instant, and are then off to some other place around, proceeding with restless activity to gratify the calls of hunger and the stimulus of caprice. Thus they are seen to rove along for miles together, until satisfied or fatigued, when they retire to rest in the recesses of the darkest forests, situations which they eventually choose for their temporary domicile, where in solitude and retirement they rear their young, and for the whole of the succeeding autumn and winter remain probably together in families. When the gun thins their