Meet the Killdeer

In a high-pitched voice that carries long distances, the Killdeer calls out its name to tell all of its presence. "Kill-dee! Kill-dee! Kill-dee!" If you look up, you may see a slender-winged, robin-sized bird flitting this way and that at high speeds.

Killdeer have several calls, but this flight call is by far the best known, and gave the bird its English name. Their Latin name, Charadrius vociferous, speaks to their noisy behavior as well. Usually easy to recognize, Killdeer are the largest of the ringed plovers, and the only one in their range to have a double breast-band. On the ground, they have a jerky, exploratory style; quick bursts of running interspersed with pauses to look around. When they're slightly alarmed, such as when they spot a human, they often bob their whole bodies up and down briefly, as if they're trying to get a different angle on things. In the air, killdeer are graceful, quick fliers with stiff wing-beats, similar to American kestrels in their flight pattern.

Killdeer are well-known for reasons beyond their recognizable flight call. Found throughout North America as far north as the tundra, with some populations ranging as far south as northern South America, they can be seen all over the U.S. Moreover, they are birds of flat spaces, and are as happy to use human-made spaces as natural ones. They're found on cultivated fields, lawns, golf courses, athletic fields, gravel roofs and parking lots, in addition to natural meadows, grasslands, mudflats and sandbars. Unlike most other plovers and similar shorebirds, killdeer are often found far from water. They are a familiar bird species even to many people who don't make it far beyond the city.

A specialist of the wide open spaces, killdeer feed on the ground and eat a variety of insects, earthworms, snails and seeds. Adaptable foragers, they will follow the farmer's plow and eat whatever gets turned up in the dirt or killed, and have been observed hunting frogs. They will feed on mudflats and in water as well, but unlike most so-called shorebirds, their real specialty is feeding on dry ground.

They nest on the open ground, too, leaving their nests especially vulnerable to danger. They've developed a couple of specialized behaviors to deal with this, the most infamous of which is the "broken-wing display." Although not the only birds to exhibit this behavior, they're certainly the best-known.

A predator is approaching the nest. They probably don't know the nest is there -- most predators find killdeer nests accidentally, because the nest, eggs and chicks are all extraordinarily well-camouflaged. But the nest in in danger, even so. But, wait, what's that over there? Some distance from the nest, in a different direction, is an adult killdeer -- and it appears to be in trouble. One wing is hanging limply and the bird stumbles and calls as if mortally wounded. The predator senses an easy meal and heads towards the injured bird, but the killdeer stays just out of reach. The predator follows it a distance, well away from the area of the nest. Suddenly the bird flies away, magically healed, and lets out a triumphant "kill-dee!"

It was a trick, of course, to lure the predator from the nest. Killdeer will perform this behavior for humans, too, judging them to be possible predators. If you see what seems to be an injured killdeer, don't worry -- he's probably fine. But watch where you step. Killdeer nests are occasionally destroyed when unobservant people accidentally crush them.

This isn't the only ploy killdeer use to protect their nests. The broken-wing display works well on predators, but it doesn't work on cattle and other large mammals who aren't looking to make a meal of a nest, but could easily crush it. Instead, when a large hoofed mammal approaches the nest, the parent killdeer fluff up and spread their tails to make themselves look as large as possible, and rush at the animal in a menacing fashion. Small as they are, this threatening display often convinces the largest animals to take a different path.

The nest these killdeer parents work so hard to protect is little more than a shallow scrape on the ground. The preferred site is on gravel, but they will also nest on bare dirt or sand, even on pavement, or will scrape a depression into grass. Although they don't truly build a nest, they will decorate their shallow depression with small rocks, pieces of shell, twigs, even bits of trash -- to what purpose no one knows for sure. It may aid in camouflaging the nest, especially in disguising the shapes of the eggs. The eggs are already well-camouflaged, buffy in color with heavy dark speckling. Four eggs is average, ranging from two to five.

After 22-28 days, the chicks hatch. Like the eggs, they're buffy brown and speckled, but already have some of the distinctive banded markings of the adults. Killdeer chicks are precocial, and hatch with a heavy covering of down and opened eyes, ready to run around and begin searching for food as soon as they dry. With their oversized, overlength legs, fluffy down and big dark eyes, killdeer chicks are downright adorable. The chicks grow fast, and within a few weeks are on the wing. Some killdeer pairs can raise two broods in a season, before cold weather shuts down the supply of suitable insects and they must move south.

Killdeer are migratory, moving south with their cold-blooded food supply and wintering in the southern half of the U.S., Mexico, Central America, and the northernmost part of South America. They return to their northern haunts soon enough, often as early as February and March, when their distinctive "kill-dee!" calls can be heard once again over the cold, crisp American grasslands... and even a few parking lots.

Sources:
http://www.allaboutbirds.org/guide/Killdeer/lifehistory
http://en.wikipedia.org/wiki/Killdeer
http://www.seattleaudubon.org/birdweb/bird_details.aspx?id=145
http://www.birdwatching.com/stories/killdeer.html