CALIFORNIA BLUE GROSBEAK. Guiraca caerulea salicarius Grinnell

Field characters.—Decidedly larger than Junco or Linnet; tail shorter than body; bill heavy, very thick at base. Sexes different. Adult male: Almost solidly dark blue; wing with a broad bar of reddish brown. Female and young: Pale yellowish brown, the wings and tail darker; two light bars across wing. Behavior similar to that of Linnet. Voice: Song of male a rather weak rhythmical warble of short duration and uttered at relatively long intervals; call note of both sexes a sharp clink.

Occurrence.—Common summer visitant in Lower Sonoran Zone. Found by us only at Snelling. Lives in willows and similar vegetation along river bottoms. To be seen singly or in pairs.

The California Blue Grosbeak is restricted to the Lower Sonoran Zone where it lives in the low dense thickets of willow on the bottom lands of the big rivers. It is therefore not likely to come to the attention of the mountain-seeking visitor unless he should stop off at some place in the lowlands and make special search for the bird.

The blue grosbeak takes its name from the color of the male bird which is almost entirely blue of a dark ultramarine hue and not cerulean or the usual sky blue as one of the scientific names of the species would suggest. The female and young birds are almost solidly brown, with no conspicuously contrasted markings. Not infrequently breeding males are to be seen which have only a few irregular patches of blue on an otherwise brownish plumage. The males in this imperfect stage have their wing and tail feathers much more worn than those of the males with full blue plumage. This latter fact suggests that the birds in mixed plumage are of the previous season's brood and hence just under a year in age. The flight feathers acquired in the nest (juvenal plumage) are not shed at the first fall molt. These feathers, retained throughout the first year of life, show relatively more wear than the wing and tail feathers of the adults, which are newly acquired at some time in the fall following completion, for the season, of the nesting duties.

The blue grosbeak is the only one of our emphatically big-billed finches which has blue in its scheme of coloration, and it can be distinguished, as regards the male, on this score alone. The Lazuli Bunting, which is conspicuously blue (of a lighter tone) is much smaller, with white on belly and with a smaller bill. The Western Bluebird is slender of bill and brown of chest.

During the nesting season the blue grosbeak seems to prefer the vicinity of water, the banks of an irrigating ditch grown up to tall weeds or willows being an acceptable location. After the broods are reared the birds range more widely and often invade much drier situations. They do not linger long in the region, and after the middle of July, few if any are to be seen. The fall molt is deferred until after the birds leave our latitude for their far southern winter home.

At Snelling, on May 26, 1915, 6 blue grosbeaks were seen during a three-hour trip through the bottom lands of the Merced River. At that season wild blackberries were bearing abundantly and these grosbeaks in company with other species had been feasting on the berries.