KILLDEER. Oxyechus vociferus vociferus (Linnaeus)

Field characters.—A Plover, about size of Robin. Two black bands across chest, white collar around hind neck, white bar across wing, tawny rump, white under surface and brown upper surface, and white-tipped and black-banded tail. Voice: A shrill, plaintive kill-dee or kill-deer, oft repeated.

Occurrence.—Common resident in lowlands and western foothill territory. Also occurs during summer at east base of mountains about Mono Lake; casual in Yosemite Valley and on Tuolumne Meadows. Frequents wet meadows, and pond and stream margins, associating in pairs or small flocks.

The familiar noisy Killdeer is a common resident in the western part of the Yosemite region, for example, about Snelling and Merced Falls. Small numbers occur during the summer months about Mono Lake where they nest, while individual birds occasionally stray to higher intervening localities, such as Tuolumne Meadows. While technically a typical shore bird and hence thought of as a water bird, the presence of mere seepage is enough to attract and hold a pair of Killdeers. Wet meadows are characteristic forage grounds.

About a rain pool on the plateau land near Forty-nine Gap, west of Pleasant Valley, five or six were seen on May 28, 1915. They trotted about, bobbing up and down at intervals, permitting one to approach them to within 50 feet, and showing clearly all of their distinctive color markings. The noise of a gun startled them quickly into flight, whereupon they began to circle upward until they were a hundred yards or so above the ground. For three or four minutes after the shot they continued their wild circling flight and kept up a torrent of cries. Then they began to quiet down and soon descended to the ground, to resume their intent search for food.

The striking pattern of coloration, four black cross-bars on a white and brown background, proves to be highly disruptive in effect when the Killdeer is standing still on a pebble-covered flat; in other words, the bird becomes invisible. The smooth gliding run practiced by the birds renders them much less conspicuous and more difficult to follow with the eye than if they were to hop along jerkily in the manner of sparrows.

On the pebbly shores of Bean Creek, east of Coulterville, a nest of the Killdeer was found on June 6, 1915. The 4 darkly splotched eggs were placed, with no attempt at concealment, and without lining of any sort to provide a softer resting place, in a slight depression in the gravel. When we were yet a hundred yards distant on the bank above, the parent bird flushed. As we approached she ran along ahead of us. Now and then she would squat down, adjust her wings, and proceed to incubate—pebbles! Failing in this ruse she trailed her wings as if they were broken, or again played innocently about the creek shore, alternately attempting to decoy us from the eggs and appearing unconcerned. All the while the eggs were resting in the glaring sun on gravel that was hot to our hands.

When we camped along the Tuolumne River below Lagrange from May 5 to 9, 1919, a pair of Killdeer was found to be occupying a pebbly flat of ten acres or so at the side of the river. The birds raised a commotion whenever we stirred about in the vicinity of the flat, but much minute searching was necessary before the nest was actually located. The sitting bird never flew up directly from the nest; but always when the observer was yet 50 yards or so away she (or he) slipped quietly off and slunk along for 50 or 100 feet with head depressed. Then the bird would begin to cry and call and presently fly off with a great clamor, soon to be joined by the other of the pair. The two would then act greatly concerned no matter where the observer went so long as he remained on the flat. The initial 'sneak' of the sitting bird was the critically valuable ruse, but the tactics all through were unquestionably effective. The nest was found to consist of a slight depression in the gravelly and pebbly ground of the open river bottom. The depression was sprinkled with grayish tips of a dead and withered weed and this lining was the only feature which rendered the spot at all different from its surroundings. There was only one egg; yet the bird had been sitting on it persistently during the preceding two days. The egg showed no evidence of incubation and was likely infertile. Ordinarily 4 eggs constitute a set. Less often there are 3 and rarely 2. Another pair of Killdeer in the neighborhood behaved as though they had their nest on a bit of ground closer to the river, but no search was made for it.

One bird of the pair which owned the nest with one egg was seen repeatedly to squat down on the ground, a long distance from its nest, and to vibrate the tail slightly, at the same time uttering a low crooning trill. Another bird in a plowed field in the same general region did the same, as did also a Killdeer seen on Blacks Creek near Coulterville a few days later. Evidently birds of this species are thoroughly conscious of being watched and go through a variety of deceptive tactics in an attempt to mislead anyone who even distantly approaches their nests.

At Walker Lake, September 14, 1915, a Killdeer was seen in a fenced pasture, while in early July of the same year one was repeatedly flushed from a certain area on Tuolumne Meadows near the Sierra Club headquarters at Parsons Lodge. The behavior of the latter bird suggested nesting, but no mate was seen. Proof of the nesting of the Killdeer at so high an altitude remains yet to be obtained.

The species was seen along the banks of the Merced River in Yosemite Valley, June 20 to 25, 1893 (Emerson, 1893, p. 178), and there is the possibility that nesting has occurred there.