Plumages.—Robert Ridgway (1919) describes the downy young stilt as follows:
Upper parts light buffy grayish mottled with dusky, the back and rump with several large blotches of black; head, neck, and under parts buffy whitish or brownish white, the crown, occiput, and hind neck grayish, the crown with a mesial streak of black, the occiput with several irregular spots of the same.
The juvenal plumage appears first on the scapulars, back and breast; and the tail is the last to appear. The young bird is fully feathered, except the tail, by the time it is two-thirds grown. In fresh juvenal plumage the color pattern is much like that of the adult female; the crown, hind neck, back and wings are brownish black, all the feathers being edged or tipped with "cinnamon"; the edgings are narrowest on the head, upper back and wing coverts, and broadest on the scapulars and tertials; the face, sides of the head and all under parts are white; the central tail feathers are dusky and the others are white, washed with dusky near the tip, and all tipped with pinkish buff. This plumage is worn all through the fall and winter, with no change except by wear and fading; before winter the edgings have largely disappeared.
A partial prenuptial molt of the body plumage occurs in early spring, when young birds become indistinguishable from adults, except for some retained juvenal wing coverts. Adults probably have a partial prenuptial molt in early spring and a complete postnuptial molt in late summer, but there are no well marked seasonal differences in plumage.
Food.—Doctor Wetmore (1925) writes:
Stilts feed by picking up insects on muddy shores or in shallow water, and though not averse to frequenting alkaline areas, on the whole prefer fresher water than do avocets. For detailed analysis, 80 stomachs of the black-necked stilt were available, distributed from March to August, and collected in California, Utah, Florida, and Porto Rico. Vegetable food in these amounted to only 1.1 per cent, whereas the animal matter formed 98.9 per cent. The birds are adept in seizing rapidly moving prey and in general are very methodical in their manner of obtaining food. Gravel is picked up to some extent to aid digestion, and part of the seeds taken may have been swallowed for the same purpose.
The animal food consisted mainly of insects, aquatic bugs and beetles making up the largest items; dragonfly nymphs, caddisflies, mayfly nymphs, flies, billbugs, mosquito larvae, and grasshoppers were included. Crawfishes, snails, and a few tiny fishes were eaten. The vegetable food consisted mainly of a few seeds of aquatic and marsh plants.
Behavior.—The flight of the stilt is steady and direct, but not particularly swift; the bill is held straight out in front and the legs are extended backwards, giving the bird a long, slim appearance. Over their eggs or young, stilts sometimes hover on steadily beating wings with dangling legs. In their excitement they sometimes climb up into the air and make startling dives.
But stilts are essentially waders; for wading they are highly specialized, and here they show to best advantage. At times they seem a bit wabbly on their absurdly long and slender legs, notably when trembling with excitement over the invasion of their breeding grounds. But really they are expert in the use of these well-adapted limbs, and one can not help admiring the skillful and graceful way in which they wade about in water breast deep, as well as on dry land, in search of their insect prey. The legs are much bent at each step, the foot is carefully raised and gently but firmly planted again at each long stride. The legs are so long that when the bird is feeding on land it is necessary to bend the legs backward to enable the bill to reach the ground.
Stilts can swim and even dive if necessary, but they are very awkward at both, as might be expected with such long legs and the absence of webbed feet; they never indulge in either action except in cases of dire necessity. They are usually gentle and unsuspicious birds, much more easily approached than most large waders. On their breeding grounds they are especially fearless and demonstrative. Some of their amusing antics are well described by Mr. Dawson (1923) as follows: