Scientific Name: Charadrius vociferous
(Information for this species page was collected, in part, by Nancy Sinegal and Jamie Calligaro for their Biology 220W classes in Spring 2004 and Spring 2006)
The killdeer (Charadrius vociferous) is the most widely distributed member of the plover family of birds. Plovers are dominantly shorebirds, but the killdeer, in addition to being a common member of the seaside avian fauna, is also found far inland in a great variety of upland, terrestrial habitats. It is a common bird of grasslands, farmlands, golf courses, mud flats, parking lots, and even the flat graveled roofs of buildings (a population of killdeer have lived and bred for years on the flat roofs of the campus buildings very close to the site of our Nature Trail). The killdeer is found throughout North America, Central America, the islands of the Caribbean, and into the northern portions of South America as far as southern Peru. It migrates out of its northernmost ranges but is a year-round resident of the southern United States and the remainder of its warm-temperate and tropical distribution.
The killdeer is between 8 and 11 inches long and has a wingspan of 18 to 19 inches. It has long legs, a short neck, long wings, a long beak, and a long tail. It weighs between 2.6 and 4.5 ounces. It is brownish gray on its back and white on its belly. The key identification characteristic of the killdeer, though, is the presence of three, black bands or rings that encircle the upper part of its body. Two of the rings wrap around the upper breast and the third wraps around the head. The head band splits around the eyes to form the bird’s very distinctive black mask. The killdeer also has a set of vividly colored, reddish orange rump feathers which are visible in flight and also during certain behavioral displays. Males, females, and juveniles all have the same basic plumage colorations and markings. Juveniles, though, only have a single dark breast band.
The killdeer migrates back to its northern breeding ranges in late winter or early spring. Its arrival in mid-March or early April is often the first appearance of a season migrant in an area. For the past 7 years, the killdeer have regularly returned to our Nature Trail in the second week of March frequently facing very cold and even snowy weather for the next three to four weeks. The loud, screaming cry of the killdeer is a song which announces the eventual possibility of spring’s arrival if not its exact presence. The breeding season begins in March, peaks in April and May, and may even extend into June. Two broods a year are possible in most locations and there have even been reports of fall nesting and breeding in killdeer populations in the southern United States. Fall reproduction is a very rare phenomenon in shorebirds.
Males typically arrive first in a region and work vigorously and vociferously to claim a breeding territory. A given male may claim the same territory for several years in a row. The males often exhibit a hovering, slow wing beating flight behavior (accompanied, like most behavioral displays of the species, with loud, raucous calling) in order to announce their territorial possessions, presence, and availability. Males along with the late arriving females then carry out elaborate, soil scrapping behaviors (and duets of loud, calling) within the breeding territory. One of these scrape sites becomes the chosen nest site.
The nest consists of a 5 to 7 inch diameter shallow concavity in the soil or rocky substrate. It may be completely unadorned and unmodified by the bird, or it may have a few added rocks around its edges or bits of plant material laid upon it. The killdeer lays on average four eggs in the nest (ranges from 2 to 6 eggs). The eggs are a very neutral buff color with cryptically arranged black blotches that greatly enhance their camouflaged appearance. The eggs are very difficult to see even when you know the precise location of the nest! Both male and female incubate the eggs. The long, 28 day incubation period allows the chicks to undergo quite advanced development prior to hatching. The chicks are fully feathered and are able within an hour or so of hatching to run, leave the nest, and even begin foraging for their own food. The parental birds guard the chicks but take no role in their direct care or feeding. The parents may, in fact, begin their second brood when the first set of eggs hatch. The parents then alternate between roles of incubators and chick protectors until the second clutch hatches.
Killdeer forage for food both during the day and also at night. They are omnivorous and opportunistically consume a wide variety of insects (including beetles, grasshoppers, flies, caterpillars, grubs, and mosquitoes), other invertebrates (including ticks, spiders, snails, and earthworms), and many types of berries and plant seeds.
A very distinctive behavior exhibited by the killdeer is its remarkable “broken wing” or “injured bird” display. In this behavior, the adult bird lures a potential predator away from a nest (or group of chicks) by holdings its wings in a crooked, dragging orientation and by then thrashing about in the grasses and weeds of its habitat while vocalizing (of course) in a loud and very distressed manner. The predator (or confused naturalist!) is inevitably drawn to the sight and sound of the flailing bird and is thus pulled away from the locus of the nest or chicks. The adult will continue this behavior until it determines that a sufficient distance has been established between the predator and its eggs or young. The adult then flies away raucously calling and returns to the nest or chicks later on.
The killdeer is very tolerant of humans and can live and reproduce in a wide range of human-modified habitats. Habitat destruction, though, and the impacts of herbicides and pesticides, farm and construction machinery, lawnmowers, cars, and trucks have significantly reduced the population densities of this vigorous and extremely interesting species.