Killdeer - WikiHQ

The killdeer (Charadrius vociferus) is a large plover found in the Americas. Its shrill, two-syllable call is often heard, sounding like "kill deer". It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his Systema Naturae. Three subspecies are described. Its are mostly brown with rufous fringes, the head has patches of white and black, and two black bands cross the breast. The belly and the rest of the breast are white. The nominate (or originally described) 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 resident in the West Indies, and C. v. peruvianus inhabits Peru and surrounding South American 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 nonbreeding habitat of the killdeer includes coastal wetlands, beach habitats, and coastal fields. Its breeding grounds are generally open fields with short vegetation (but locations such as rooftops are sometimes used); although it is a shorebird, it does not necessarily nest close to water. The nest itself is a scrape lined with vegetation and white material, such as pebbles or seashell fragments. This bird lays a clutch of four to six buff to beige eggs with dark markings. The breeding season (starting with egg-laying) occurs from mid-March to August, with later timing of egg-laying in the northern portion of the range. Both parents incubate the eggs for 22 to 28 days typically. The young stay in the nest until the day after being hatched, when they are led by their parents to a feeding territory (generally with dense vegetation where hiding spots are abundant), where the chicks feed themselves. The young then fledge about 31 days after hatching, and breeding first occurs after one year of age.

The killdeer primarily feeds on insects, although other invertebrates and seeds are eaten. It forages almost exclusively in fields, especially those with short vegetation and with cattle and standing water. It primarily forages during the day, but in the nonbreeding season, when the moon is full or close to full, it forages at night, likely because of increased insect abundance and reduced predation during the night. Predators of the killdeer include various birds and mammals. Its multiple responses to predation range from the "broken-wing display" (feigning injury to lure a predator away from the nest) to the "ungulate display" (charging the animal, named for its use against grazing ungulates rather than predators).

The killdeer was formerly considered a least-concern species by the IUCN due to its large range and population, where he called it the "chattering plover". The genus name Charadrius is Late Latin for a yellowish bird mentioned in the fourth-century Vulgate Bible. This word derives from the Ancient Greek kharadrios, a bird found in ravines and river valleys (kharadra, "ravine"). The specific name vociferus is Latin, coming from vox, "cry", and ferre, "to bear".

Three subspecies are described:

C. v. vociferus <small>Linnaeus, 1758</small> – The nominate subspecies (originally described subspecies), it is found in the US (including southeastern Alaska), southern Canada, Mexico, and with some less widespread grounds further south, to Panama. It winters to northwestern South America.

– This South American subspecies is found in western Ecuador, Peru, and extreme northwest Chile. Adults ranging in length from , having a wingspan between , and usually being between in weight.

thumb|left|In flight

Its upper parts are mostly brown with rufous fringes, found throughout the year in most of the contiguous United States. It also winters south to Central America, the West Indies, Colombia, Ecuador, and islands off Venezuela, leaving its breeding grounds after mid-July, and ends in mid-May.

The subspecies C. v. ternominatus is thought to be resident in the Bahamas, Greater Antilles, and Virgin Islands. C. v. peruvianus is seen year-round in western Ecuador, Peru, and extreme northwestern Chile. Although generally a low-land species, 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 tall), Nests are also sometimes located on rooftops. The nest itself is merely a shallow depression 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 to 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.

thumb|A female on a [[bird nest|nest in Pennsylvania]]

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 Puerto Rico, and possibly in other Caribbean islands, breeding occurs year-round. 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 , 76% of the time around , and 87% of the time at about . When it is hot (above at least ), incubation cools the eggs, generally through shading by one of the parents.

thumb|left|Eggs in a nest on the ground

About 53% of eggs are lost, 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.

thumb|A chick in [[New Jersey]]

When a pair has two broods, the second is usually attended by just the male (which can hatch the eggs on his own, unlike the female). In this case, the male does not spend most of the time standing; the amount of time he does stand, though, stays constant as the chicks age. Like attentive adults in two-parent broods, the sole parent increases the time spent foraging as the young age.

Feeding

The killdeer feeds primarily on insects (especially beetles and flies), in addition to millipedes, worms, snails, spiders, and some seeds. It opportunistically takes tree frogs and dead minnows. Viable disseminules can be recovered from killdeer feces, indicating that this bird is important in transporting aquatic organisms.

The killdeer uses visual cues to forage. An example of this is "foot-trembling", where it stands on one foot, shaking the other in shallow water for about five seconds, pecking at any prey stirred up. When feeding in fields, it sometimes follows plows to take earthworms disturbed to the surface. It is preyed upon by American herring gulls, common crows, raccoons, and striped skunks.

Responses to predators

The parents use various methods to distract predators during the breeding season. One method is the "broken-wing display", also known as "injury feigning". Before displaying, it usually runs from its nest, making alarm calls and other disturbances. When the bird has the attention of the predator, the former turns its tail towards the latter, displaying the threatening orange color of the rump. It then crouches, droops its wings, and lowers its tail, which is more common for them.

File:No one can fake an injury like a Killdeer (34125990963).jpg

File:Charadrius vociferus -distraction display to protect nest-8.ogv

File:Charadrius vociferus tx1.jpg

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The intensity of the responses to predators varies throughout the breeding season. During egg-laying, the most common response to predators is to quietly leave the nest. As incubation starts and progresses, the intensity of predator responses increases, peaking after hatching. This is probably because it is worth more to protect the young then, as they are more likely to fledge. After hatching, reactions decrease in intensity, until a normal response is called. This is because the young become more independent as they age.

Conservation status

The killdeer was formerly considered a least-concern species by the IUCN due to its large range of about and population, estimated by the IUCN to be about one million birds, and in Canada by the Migratory Birds Convention Act.

Notes

References

Feeding

Responses to predators

Conservation status

Notes

References

External links