There is quite an appreciable difference between specimens of this species from Washington Territory and California; the latter are smaller, the under parts paler. In the series before us, however, we see no grounds for specific distinction. [Illustration: _Psaltriparus minimus._] HABITS. This interesting little species was first added to our fauna by the indefatigable Mr. Townsend in 1837. It is abundant throughout the Pacific coast from Fort Steilacoom to Fort Tejon. Dr. Gambel found it exceedingly abundant both in the Rocky Mountains and throughout California. During the winter the otherwise cheerless woods were alive with the busy and noisy troops of these restless and industrious birds, gleaning their scanty fare in company with the _Reguli_, in every possible position and manner, from bush and tree. He describes their anxious solicitous search for food as quite curious. They kept up a continual twittering, and so intent were they in their employment that they appeared to lose sight of all danger, and it was by no means unusual to be so surrounded by a flock as almost to render it possible to catch them in the hand. Dr. Cooper found this species abundant in Washington Territory, but never met with it north of the Columbia River. Dr. Suckley says it is quite common at Fort Steilacoom. He could not, however, detect any difference in its habits from those of other species of this family. He saw none in Washington Territory during the winter, and presumes they all migrate to the South, though the _rufescens_ and the _occidentalis_ are found there throughout the winter. Townsend, however, speaks of it as a constant resident about the Columbia River, hopping around among the bushes, hanging from the twigs in the manner of other Titmice, twittering all the while with a rapid enunciation resembling the words _thshish tshist-tsee-twee_. Mr. Nuttall first observed their arrival on the banks of the Wahlamet River about the middle of May. They were very industriously engaged in quest of insects, and were by no means shy, but kept always in the low bushes in the skirts of the woods. On one occasion the male bird was so solicitous in regard to the safety of the nest as to attract him to the place where, suspended from a low bush, about four feet from the ground, hung their curious home. It was formed like a long purse, with a round hole for entrance near the top, and made of moss, down, lint of plants, and lined with feathers. The eggs were six in number, pure white, and already far gone toward hatching. In the following June, in a dark wood near Fort Vancouver, he saw a flock of about twelve, which, by imitating their chirping, he was able to call around him, and which kept up an incessant and querulous chirping.