Mr. Ridgway mentions the E. pusillus as the most common of the Empidonaces in the Great Basin, as well as in California and the Rocky Mountains. It is chiefly, if not entirely, confined to the willows along streams, but it is as common in the river valleys as in the mountain “parks.” In all respects it is a counterpart of the E. trailli; its notes, as well as its manners, being the same. In Parley’s Park, in the Wahsatch Mountains, at an elevation of over 7,000 feet, they were breeding abundantly; about nightfall they became particularly active, chasing each other, with a merry twitter, through the willow thickets, or, as they perched upon a dry twig, uttered frequently, with swelling throats and raised crest, their odd but agreeable enunciation of pretty dear, as their notes were translated by the people of the locality.
In the Department of Vera Cruz, Mexico, Mr. Sumichrast gives this species as a summer resident within the temperate region. He found it quite common around Orizaba in the months of June and July.
It was also met with on the Mexican Boundary Survey in summer, having been taken in June at Los Nogales by Dr. Kennerly, and at Rio Nazas, in Durango, by Lieutenant Couch, the same month.
Dr. Coues mentions it as moderately plentiful as a summer resident in Arizona. None of this genus were very common at Fort Whipple, but this one was by far the most characteristic species. It arrives there about the middle of April, and remains through September.
Dr. Suckley found this species quite abundant in the vicinity of Fort Steilacoom, where it arrives early in May. It seems to prefer the vicinity of bushes and low trees at the edges of dense forests. This species, he adds, is rather less pugnacious than others of the group, and in habits generally more resembles the Vireo family. Its notes are said to be short but sweet, and just after sundown on warm summer evenings particularly low, plaintive, and soothing.
Dr. Cooper speaks of it as found by him frequenting the dark and gloomy spruce forests, which it seems to prefer to more open places. He found it most numerous near the coast, but also saw a few at Puget Sound, where it arrived about the 25th of April. He speaks of its song as lively but monotonous. He found it very difficult to get a sight of this bird among the upper branches of the tall spruces, its color making it almost invisible in
the shade. One of these birds was observed to keep constantly on the border of a small pond and to drive away a Kingbird from the place. He adds that it has a peculiar short and lisping song of three notes, very different from those of the other species. In the fall the young birds uttered a very different call-note.
Mr. Ridgway found this species breeding, June 23, at Parley’s Park, Utah. One nest was built on the horizontal branch of a willow, over a stream, about four feet from the ground. It was partly pensile. It was three inches deep and four in diameter; the cavity was two inches wide and one and a half deep. Externally the nest was somewhat loosely constructed of flaxen fibres of plants, soft strips of inner bark and straw, and lined more firmly with fine roots of plants. This structure was firmly bound around the smaller branches of the limb. The inner nest was much more compactly interwoven than the periphery. The eggs, four in number, were of a chalky whiteness, more pinkish when unblown, finely sprinkled at the larger end with reddish-brown dots. Length, .77 of an inch; breadth, .51.
Another nest from the same locality was built in the upright fork of a wild rose, in the undergrowth of a willow thicket, and about four feet from the ground. It is a much more compact and homogeneous nest. Its external portion was almost wholly composed of the interweaving of the fine inner bark of deciduous shrubs, blended with a few stems of grasses, feathers, etc., and is lined with a few fine grass stems and fibrous roots. The eggs, four in number, have a pinkish-white ground, and are spotted at the larger end with reddish-brown and chestnut spots, in scattered groups.
In the summer of 1870 a son of Mr. Thure Kumlien, of Jefferson Co., Wisconsin, found the nest and eggs of this species. Both parents were obtained, and were fully identified by Professor Baird. The nest was placed in a thick mass of coarse marsh grasses, near the ground, and firmly interwoven with the tops of the surrounding herbage. The grass and reeds, among which it was made, grew in the midst of water, and it was discovered by mere accident in a hunt for rail’s eggs. It was found, June 28, on the edge of Lake Koskonong. It is a large nest for the bird; its base and sides are made of masses of soft lichens and mosses, and within this a neat and firm nest is woven of bits of wool and fine wiry stems of grasses, and lined with the same. The eggs measure .70 by .54 of an inch, are white with a pinkish tinge, and are marked with reddish-brown and fainter lilac blotches at the larger end.