As one approaches a feeding flock, he notes the eagerness with which the birds run forward, or rise and flit past their fellows, now diving at a nimble weevil, now leaping to catch a passing bug, but always pushing on until one perceives a curious rolling effect in the total movement.
As we draw near, some timid individual takes alarm, and instantly all are up, to alight again upon the fence or shrubbery where they clack and whistle, not so much by way of apprehension as thru sheer exuberance of nervous force. As we pass (we must not stop short, for they resent express attention) we note the droll white eyes of the males, as they twist and perk and chirp in friendly impudence; and the snuffy brown heads of the females with their soft hazel irides, as they give a motherly fluff of the feathers, or yawn with impatience over the interrupted meal. When we are fairly by, the most venturesome dives from his perch, and the rest follow by twos and tens, till the ground is again covered by a shifting, chattering band.
Like all Blackbirds, the Brewers are gregarious; but they are somewhat more independent than most, flocks of one or two score being more frequent than those of a hundred. During migrations and in autumnal flocking they associate more or less with Redwings; but, altho they are devoted to the vicinity of water, they care nothing for the fastnesses of reed and rush, which are the delight of Redwing and Yellowhead. Their preference is for more open situations, so that they are most abundant upon the East-side. Here a typical breeding haunt is a strip of willows fringing a swamp; or, better still, a line of dark green thorn-bushes clinging to the bank of the rolling Columbia.
Altho isolated nests may now and then be found, colonies are the rule; and I have found as high as forty nests in a single patch of greenery. There is room, of course, for individual choice of nesting sites, but the community choice is the more striking. Thus, one recalls the greasewood nesting, the rose-briar nesting, the thorn-bush nesting, where all the members of the colony conformed to the locally established rule in nest position. Mr. Bowles records the most remarkable instance of this: One season the nests of the South Tacoma colony were all placed in small bushes, the highest not over four feet from the ground; but in the season following the birds were all found nesting in cavities near the top of some giant fir stubs, none of them less than 150 feet from the ground. On the other hand, in the Usk nesting of 1906, on the placid banks of the Pend d’Oreille, one pair had recessed its nest in a stump at a height of eighteen feet, while three other pairs had sunk theirs into the ground at the base of bushes.
In construction the nest of the Brewer Blackbird varies considerably, but at its best it is quite a handsome affair. Composed externally of twigs, weed-stalks, and grasses, its characteristic feature is an interior mould, or matrix, of dried cow-dung or mud, which gives form and stability to the whole. The lining almost invariably includes fine brown rootlets, but horsehair is also welcomed wherever available.
The eggs of Brewer’s Blackbird are the admiration of oölogists. Ranging in color from clear greenish gray with scattered markings thru denser patterns to nearly uniform umber and chocolate, they are the natural favorites of “series” hunters. The range of variation is, indeed, curious, but it proves to be entirely individual and casual without trace of local or constant differences. Eggs from the same nest are usually uniform in coloration, but even here there is notable diversity. In some instances, after three or four eggs are laid, the pigment gives out, and the remainder of the set is lighter colored. Again, single eggs are heavily pigmented half way, and finished with a clear green ground-color.
Fresh eggs may be taken in the Yakima country during the last week in April, and in one case noted, deposition began on April 14th; but May 1st-15th is the usual rule there and elsewhere. Five eggs is the common set, but six to a clutch is not rare. Of twenty-eight nests examined in Yakima County, May 4, 1906, eleven contained six eggs each; while, of something over two hundred seen altogether, two nests contained seven each.
Taken in Stevens County. Photo by the Author.
GROUND NEST OF BREWER BLACKBIRD.
It is in his notes that the Brewer Blackbird betrays his affinities best of all. The melodiously squeaking chatter of mating time is, of course, most like that of the Rusty Blackbird (S. carolinus), but it lacks the bubbling character. He has then the swelling note of the Grackles proper, fff-weet, the latter part rendered with something of a trill, the former merely as an aspirate; and the whole accompanied by expansion of body, slight lifting of wings, and partial spreading of tail. This note is uttered not only during the courting season, but on the occasion of excitement of any kind. Kooreé has a fine metallic quality which promptly links it to the Keyring note of the Redwing. Chup is the ordinary note of distrust and alarm, or of stern inquiry, as when the bird-man is caught fingering the forbidden ovals. A harsh low rattle, or rolling note, is also used when the birds are squabbling among themselves, or fighting for position.