page_title: Killdeer
section_title: Breeding
hierarchical_section_title: Killdeer / Behavior / Breeding
caption_attribution_description: Four Killdeer eggs in grassy depression.
context_page_description: The killdeer is a large plover found in the Americas. It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae. There are three subspecies. The killdeer's common name comes from its often-heard call. Its upperparts are mostly brown with rufous fringes, the head has patches of white and black, and there are two black breast bands. The belly and the rest of the breast are white. The nominate subspecies breeds from southeastern Alaska and southern Canada to Mexico. It is seen year-round in the southern half of its breeding range; the subspecies C. v. ternominatus is probably resident in the West Indies and C. v. peruvianus inhabits Peru and areas of the surrounding countries throughout the year. North American breeders winter from their resident range south to Central America, the West Indies, and the northernmost portions of South America.
  The non-breeding habitat of the killdeer includes coastal wetlands, beach habitats, and coastal fields. Its breeding grounds are generally open fields with short vegetation; although it is a shorebird, it does not necessarily nest close to water.
context_section_description: The killdeer forms pairs on its breeding grounds right after arriving. Both sexes (although the male more often than the female) advertise in flight with loud "killdeer" calls. The male also advertises by calling from a high spot, scraping out a dummy nest, and with killdeer flights, where it flies with slow wingbeats across its territory. Ground chases occur when a killdeer has been approached multiple times by another killdeer; similarly, flight chases occur when an individual has been approached from the air. Both are forms of territorial defense.
  The killdeer nests in open fields or other flat areas with short vegetation (usually below 1 centimeter (0.39 in) tall), such as agricultural fields and meadows. Nests are also sometimes located on rooftops. This plover frequently breeds close to where it bred the previous year. The male seems to usually renest in the same area regardless of whether or not it retains the same mate. This does not appear to be true of the female, which has been observed to not use the same territory if it does not have the same mate. The nest itself is merely a shallow depression or scrape in the ground, fringed by some stones and blades of grass. It is generally built with white nesting material instead of darker colors; the function of this is suspected to either help keep the nest cool or conceal it. In a study of piping plovers, the former function was supported, as nests were 2 °C (3.6 °F) to 6 °C (11 °F) cooler than the surrounding ground. The latter function also had some support, as the plovers generally chose pebbles closer in color to the eggs; nests that contrasted more with the ground suffered more predation. When nesting on rooftops, the killdeer may choose a flat roof, or build a nest of raised gravel, sometimes lined with white pebbles or pieces of seashells.
  The eggs of the killdeer are typically laid from mid-March to early June in the southern portion of the range, and from mid-April to mid-July in the northern part. In both cases, the breeding season itself extends to about August. In Puerto Rico, and possibility in other Caribbean islands, breeding occurs year-round.
  The killdeer lays a clutch of four to six eggs that are buff to beige in color, with brown markings and black speckles. The eggs are about 38 by 27 millimeters (1.5 by 1.1 in) in size, and laid at intervals of 24 to 48 hours. The energy expenditure of both sexes is at its highest during egg-laying; the female needs to produce eggs, and the male needs to defend its territory. Both of the sexes are closer to the nest site than usual during egg-laying and incubation, although the male is generally closer than the female during all stages of breeding. This latter fact is likely due to the male's increased investment in nest-site defense. Up to five replacement clutches can be laid, and there are occasionally two broods. Second broods are usually laid in nesting territory of the first brood. The eggs are incubated for 22 to 28 days by both the male and the female, with the former typically incubating at night. The time dedicated to incubation is related to temperature, with one study recording that killdeer incubated eggs 99% of the time when the temperature was about 13 °C (55 °F), 76% of the time around 26 °C (79 °F), and 87% of the time at about 35 °C (95 °F). When it is hot (above at least 25 °C (77 °F)), incubation cools the eggs, generally through shading by one of the parents.
  About 53% of eggs are lost, mainly to predators. The young are precocial, starting to walk within the first days of their life. After they hatch, both parents lead them out of the nest, generally to a feeding territory with dense vegetation under which the chicks can hide when a predator is near. The chicks are raised, at least in single-brood pairs, by both parents, likely because of the high failure rate of nests and the need for both parents to be present to successfully raise the young. In these broods, the young are usually attended by one parent at a time (generally the female) until about two weeks of age, after which both parent
caption: Eggs in a nest on the ground
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