Incubation is attended to by the male alone. The female, however, keeps near, and is quick to give the alarm upon the approach of danger. The females are frequently found at this time in small parties of six or eight; and should their breeding ground be approached, exhibit great anxiety, coming from every part of the marsh to meet the intruder, and, hovering over his head, utter a weak nasal note, which can be heard to only a short distance.
The movements of the birds usually render it an easy matter to decide whether or not they have nests in the immediate vicinity. After the first alarm, those having nests at a distance disperse, while the others take their course in the form of an ellipse, sometimes several hundred yards in length, with the object of their suspicion in the center; and, with long strokes of their wings, much like the flight of a killdeer, they move back and forth. As their nests are approached the length of their flight is gradually lessened, until at last they are joined by the males, when the whole party hover low over the intruder's head, uttering their peculiar note of alarm. At this time they have an ingenious mode of misleading the novice, by flying off to a short distance and hovering anxiously over a particular spot in the marsh, as though there were concealed the objects of their solicitation. Should they be followed, however, and a search be there made, the maneuver is repeated in another place still farther from the real location of the nest. But should this ruse prove unavailing, they return and seem to become fairly desperate, flying about one's head almost within reach, manifesting great distress.
Aretas A. Saunders writes to me that, in Teton County, Mont., they nest in small colonies in grassy marshes, where alkaline soil prevents the grass, mainly species of Carex and Juncus, from growing tall.
Eggs.—The Wilson phalarope almost invariably lays four eggs, rarely only three. The shapes vary from ovate pyriform to ovate and there is a slight gloss. The ground colors vary from "cartridge buff" to "cream buff," rarely "chamois." The ground color is generally well concealed by numerous markings, more or less evenly distributed. Some eggs are uniformly covered with small spots and dots, but more often these are mixed with a few larger, irregular blotches. An occasional handsome set is boldly and very heavily blotched, sometimes almost concealing the ground color. The markings are usually in very dark, brownish black or blackish brown. In some handsome sets these dark markings are mixed with "bay" and "auburn" markings. The measurements of 57 eggs average 33 by 23.4 millimeters; the eggs showing the four extremes measure 36.2 by 23.7, 33 by 25.1, 30 by 22.5 and 30.5 by 22 millimeters.
Young.—The period of incubation does not seem to be known. I can find no evidence that the female ever takes any part in it, but that she does not lose interest in her family is plainly shown by her demonstrations of anxiety when the nest is approached; probably she feels responsible for the faithful performance of his duties by her demure spouse. The male broods over the newly hatched young, protecting them from rain, or excessive heat or cold. But they are soon able to run about in a lively manner and care for themselves. Doctor Nelson (1877) writes that "the young have a fine, wiry peep, inaudible beyond a few feet." I believe that the young remain in the grassy meadows, where they can hide in safety, and do not take to the water until they are fully fledged.
Plumages.—In its natal down the young Wilson phalarope is entirely unlike the other phalaropes and quite different from any other young wader. The slender bill and long slender legs and feet are characteristic. It is prettily and distinctively colored also. The prevailing color of the upper parts and of a band across the chest is "ochraceous buff," deepening on the crown, wings, and mantle almost to "ochraceous orange," and paling to buffy or grayish white on the belly and to pure white on the chin and throat. There is a narrow, median, black line on the crown extending nearly or quite to the bill; this is continued in a broad, more or less broken, black stripe down the center of the back to a large black patch on the rump; a black spot on each side of the crown, one on the occiput and several more on wings, thighs, and sides of the back, sometimes run together to form stripes.
In fresh juvenal plumage, in July, the feathers of the crown, back, scapulars, tertials, and all wing coverts are dusky or nearly black, broadly edged with "light pinkish cinnamon" or "cinnamon buff," broadest and brightest on the scapulars; the under parts are white, but the throat, sides of the breast and flanks are washed with "pinkish buff," and the last two are mottled with dusky; the central tail feathers are broadly edged with "pinkish buff," bordered inwardly with a broad dusky band, surrounding a white area, with a dusky central streak invading it; the other tail feathers are similarly marked, but less completely patterned.
This plumage is worn for only a short time, as the body plumage and tail are molted during the last half of July and in August. By September young birds are in first winter plumage, which is like that of the adult, except that the entire juvenal wing is retained with the buff edgings faded out to white. The sexes are alike in juvenal and all winter plumages. A partial prenuptial molt in the spring, involving the body plumage and most, if not all, of the wing coverts and scapulars, makes the young bird practically adult.