CALIFORNIA THRASHER. Toxostoma redivivum redivivum (Gambel)

Field characters.—General size about that of Robin; tail long and rounded at end, equal to body in length; bill slender, sickle-shaped, over an inch in length. Coloration plain brown, dark above, paler beneath, whitish on chin. On ground runs rapidly with tail up at angle with back. Voice: Song, a series of chuckling notes, whistles, etc., in irregular sequence and given at some length; call note a low chuck.

Occurrence.—Fairly common resident of Upper Sonoran Zone on west slope of Sierra Nevada. Recorded from near Lagrange and Pleasant Valley eastward to El Portal and to Smith Creek (6 miles east of Coulterville). Lives in mixed chaparral, keeping closely to cover. In pairs.

The California Thrasher is one of the characteristic birds of the foothill chaparral belt. It rarely occurs outside of this kind of habitat, and, within the Upper Sonoran Zone is seldom missing from it. Food, nesting sites, song perches, and shelter from enemies, all as adapted to the thrasher's special needs, are found in this elfin-wood or dwarf forest which covers the foothill slopes from the margin of the San Joaquin Valley eastward to the beginning of the main forest belt on the higher mountains.

The California Thrasher is fitted in several important ways for its life amid the chaparral. Its wings are short and rounded, such wings as are required by a bird which can make only short flights within or close to cover. The tail is long, broad, and rounded, serving as an efficient rudder for quick turning in close quarters and also as a counterbalance when the bird is running on the ground. The brown plumage matches well with the earth tones beneath the chaparral, and the slender curved bill serves as both pick and rake in digging for food on the ground. The thrasher shows marked ability in escaping observation when he so chooses; to do this he drops to the ground and speeds away, using the stout legs and feet to best advantage, dodging this way or that beneath and around the bushes.

The song of the thrasher is the antithesis of a set utterance, such, for example, as that of the Yellow Warbler. It is extremely varied as to quality of the notes, and as to timing and manner of rendering. The bird has, to be sure, certain stock syllables, but these are put together in such variety that no two songs seem quite the same. The individual notes are mostly throaty, sometimes deep and rich, sometimes chuckling, occasionally like short whistles, all subject to modulation. The song recalls that of the mockingbird, but the thrasher is not nearly so much of a mimic and its notes are mellower and more subdued. The singing is most voluble in the spring months. Early morning and evening are the times most favored for singing, although on cloudy days the birds continue to sing until mid-day. For singing, the male mounts to a perch ten to twenty-five feet above the ground. An oak or elderberry bush rising well above the general level of the brush affords a suitable location. From there the thrasher's voice will travel well out over the adjacent territory; from there, at the same time, the bird is ready to drop to cover and safety at an instant's warning. Near Coulterville a thrasher was observed in song while perched just below the topmost branchlets of a 50-foot digger pine. But this was an exceptionally high position. Pairs are spaced out so widely from one another that it is not common to hear more than one male from one place. Yet near Blacks Creek two thrashers were singing in brush on opposite sides of the road and not 50 feet apart.

Thrashers are strictly resident. Hence, once the headquarters of a pair are determined, the observer may visit the place at any time of year and count on finding the birds there. Probably if one of a pair is lost the survivor soon gains a new mate, so that occupancy of the area is continued without interruption. The species is nowhere abundant; perhaps one or two pairs to a quarter section of cover is a fair average.

Near Pleasant Valley, on May 30, 1915, a California Thrasher was followed about and its regular beat determined. This bird, located a few days earlier by his singing, and his mate, lived on a rather open, south-facing rolling slope, sparsely set with blue oaks, a few digger pines, and many large old clumps of wedge-leafed ceanothus (Ceanothus cuneatus). These brush clumps in places grew so close together as to form patches a hundred feet or so across, and their very dense system of interlacing branches made an overhead cover with open spaces beneath—an effective shelter for the thrashers.

Two nests of the California Thrasher were found near Coulterville in 1919. On May 10 a nest was discovered on a gentle hill slope covered with a nearly pure stand of greasewood. It rested on a mass of slanting greasewood stems overhung by sprays of foliage of the same plant. The nest rim was 31 inches (770 millimeters) above the ground. There were 3 eggs, one infertile, one half-incubated, and the third nearly ready to hatch. The second nest was found on May 12. It was situated in a small live oak which was growing at the side of a grassy glade bounded by chaparral. The nest was 57 inches (1440 millimeters) above the ground at the rim, and was supported upon a tangle of twigs as well as by the slanting main trunk of the tree. The material used was chiefly dead twigs of greasewood with a few shreds of bark from the same shrub. The interior was lined with smaller twigs and rootlets. Outside, the nest measured approximately 7-1/2 by 12 inches (190 by 300 millimeters), while the saucer-shaped depression was about an inch deep and 4 inches across (25 by 100 millimeters). This nest was well shaded from above, although in plain view from the side. At 7:30 in the morning it contained two fresh eggs, and a third was added by 2:20 P.M. the same day.

Thrashers obtain much of their food by digging with their long bills in leafy debris under bushes; and this habit, when they chance to forage in gardens, brings them into disrepute. At the Campbell place above Pleasant Valley the birds were said to have practically dug up the garden during the summer of 1915. This is only likely to occur where cultivation is attempted close to chaparral-covered areas. General clearing and tilling of the land ordinarily results in the thrashers withdrawing from the vicinity altogether.