Chapter M: P. Skinner found that when he scared one bird from the nest, the

mate was apt to steal around behind him and take its place on the nest. He says that

In addition to their broken-wing tactics, both of the
killdeer at times would pretend to brood anywhere on the
foundation, evidently to lead me to think that that was
where their nest was. * * * On one occasion I found an
adult with one young about four days old. The youngster ran
under the old one and into its feathers; then the old bird
squatted down, covering it. Just then I saw the other bird
come running and exchange with the first parent, nestling
down over the youngster.

While the broken wing tactics are used by the birds for man, dogs, and other predatory animals, in order to draw them away from the eggs or young, quite different tactics are used for browsing animals that might step on them. Thus Howard Lacey (1911) noticed that a flock of driven goats divided. “I walked up to the place expecting to find a rattlesnake, and found instead a killdeer standing over her eggs with upspread wings and scolding vigorously.” Norman Criddle (1908) writes “If the danger came from a cow or horse, the tactics were changed and the birds with both wings and feathers spread out would run into the animal’s face, and so by startling it drive the intruder away.” This habit of scaring away a browsing animal probably accounts for the following experiences related by M. P. Skinner. The change to the broken-wing tactics appears to show great discernment and intelligence on the part of the bird.

Twice when riding near two different unsuspected nests, the
birds got up with startled cries and faced me with their
tails spread horizontally and quivering, although I was on
horseback and towered high above them. After a few moments
they made off with pretended broken wings, limping, falling
down and fluttering.

Aretas A. Saunders (1926) observed a parent very zealous in the care of its young:

This brood of young was accompanied by a parent. They
occupied a certain section of the shore of the pond, where
the young hid beneath the rushes when danger approached,
and ran over the mud flats at other times. The parent
remained near, and drove all other birds from the vicinity.
While shore birds and marsh birds were abundant all around
the Mill Pond, at this point they kept away because of the
parent killdeer. The parent was extremely belligerent, and
I watched it attack other killdeers, yellowlegs, spotted
sandpipers, soras, and song sparrows that happened to
wander in the vicinity. All birds seemed glad to leave the
vicinity.

_Plumages._--[AUTHOR’S NOTE: The most distinctive feature of the downy young killdeer is the long, downy tail, black above and elsewhere barred with “pinkish buff” and black, with long, hair-like, buffy down below protruding beyond the rest of the tail; the forehead, chin, throat, a ring around the neck and the under parts are pure white, except for a tinge of pinkish buff in the center of the forehead; a broad, black stripe above the forehead extends around the crown to the occiput; a black stripe extends from the lores, below the eyes to the occiput; there is a broad black stripe entirely around the neck, below the white; the crown, auriculars, back and inner half of the wings are grizzled “vinaceous buff” and dusky; there is a black space in the center of the back and a black band across the wing between the grizzled inner half and the white distal half.

The juvenal plumage is similar to that of the adult, but the head markings are less distinct; the feathers of the nape are tipped with “amber brown” and those of the back, scapulars, wing coverts and tertials are more or less broadly tipped or edged with the same, more broadly on the scapulars and wing coverts and more narrowly on the upper back and tertials; the intermediate white band on the breast is always more or less suffused with brownish.

The postjuvenal molt is apparently very limited and the first winter plumage is largely the juvenal plumage modified by wear. It is much like the adult except for the worn and faded edgings of the wing coverts, and some of the scapulars and tertials and the tail, which are retained. At the first prenuptial molt, which may take place from February to June, the plumage becomes practically adult.

Adults have a complete postnuptial molt, mainly in August and September, and a partial prenuptial molt of the body plumage in early spring. Nuptial and winter plumages are practically alike.]

FOOD.--The killdeer is man’s friend. It consumes great quantities of insect pests. The most complete study of its food by examination of stomachs has been made by W. L. McAtee (1912) who sums up as follows:

“In all 97.72 per cent of the killdeer’s food is composed of insects and other animal matter. The bird preys upon many of the worst crop pests and is a valuable economic factor.” Of this large proportion he finds that beetles constitute 37.06 per cent; other insects--grasshoppers, caterpillars, ants, bugs, caddis flies, dragon flies, and two-winged flies, 39.54 per cent; other invertebrates--centipedes, spiders, ticks, oyster worms, earthworms, snails, crabs, crawfish, and other crustaceans, 21.12 per cent. The 2.28 per cent of vegetable matter is chiefly made up of weed seeds such as button weed, smart weed, foxtail grass, and nightshade. He found that various kinds of weevils were eaten such as those of alfalfa, cotton boll, clover, rice, white pine, etc. In a single stomach he counted 41 alfalfa weevils.

Harold C. Bryant (1914_a_), during an outbreak of grasshoppers in California, found that the contents of one stomach was 100 per cent grasshoppers, and he estimated that each killdeer averaged 33 grasshoppers daily. Arthur H. Howell (1906) has found that the killdeer is among the most important of the birds that eat the cotton-boll weevil. Samuel Aughey (1878) found 258 locusts and 190 other insects in the stomachs of nine birds taken in Nebraska. E. R. Kalmbach (1914) found in the stomach of a killdeer taken in a western alfalfa field 316 weevils; in another 383. C. W. Nash (1909) has found the stomachs of killdeers taken in orchards completely filled with weevils. E. R. Kalmbach (1914) has also found May beetles both in adult and grub form in the stomachs, wireworms, and insects that attack sugar cane, corn, carrots, grape vine, sweet potato, tobacco, and sugar beets. Caterpillars, he found to be a favorite article of diet, also grasshoppers and crickets, crane flies and their larvae. One stomach contained hundreds of larvae of the salt marsh mosquito. He adds:

The killdeer thus befriends man, but it does something also
for the domestic animals, not only by eating horseflies
and mosquitoes, as just mentioned, but also by preying on
ticks, including the American fever or cattle tick, which
has caused such enormous losses in some parts of the South.

Arthur T. Wayne (1910) says: “This species is very partial to fields which are being ploughed, and at this time they are always very tame, following each furrow as soon as it is turned over in order to secure the worms which are exposed.” I have watched a killdeer in a ploughed field swallowing a large earthworm. Several strenuous gulps were needed before the act was accomplished.

_Behavior._--The interesting behavior of this bird during courtship and in the care of the eggs and young has already been detailed under the appropriate headings. In general it may be said that the killdeer has the usual plover habits when feeding of alternately running and then of standing still, as if to listen or look, always with head up, and of dabbing suddenly at the ground for its food. Like some other species of plover, it occasionally bobs or “teeters” in a nervous manner. This varies from a slight bob of the head, which is first hitched up and then brought down, to a bob combined with a tilting up and down of the whole body on the hips. In swift running they excel, and this serves them to good purpose in the pursuit of insects.