Killdeer are familiar shorebirds, easily recognized by their distinctive “kill-deer” call and their presence in various open habitats. These birds, about the size of a robin, have a brown back, white underside, and two prominent black bands across their chest. Unlike many shorebirds, killdeer are often found far from water, inhabiting lawns, golf courses, athletic fields, and even gravel rooftops across North and South America. Their unique behaviors, such as the “broken-wing” display to distract predators, frequently capture public interest.
The Nature of Killdeer Pair Bonds
Killdeer generally exhibit seasonal monogamy, forming a pair bond for a single breeding season. This means that while a male and female will pair up to breed and raise their young during one season, they do not necessarily remain together for life. Some pairs may reunite in subsequent years, but this is not a consistent pattern across the species. The bond typically lasts from courtship through the period of raising their young.
The concept of “site fidelity” is important when considering killdeer pair bonds. Killdeer often return to the same breeding grounds year after year. While high site fidelity can lead to re-pairing with a previous mate, returning to a location does not automatically signify a lifelong commitment. A male might return to the same area regardless of his mate, but a female may not use the territory if her previous partner is absent.
Breeding and Parental Responsibilities
During the breeding season, killdeer demonstrate cooperative parental care, sharing responsibilities for their brood’s success. The male typically claims a nesting territory and performs courtship displays to attract a female, which can include aerial displays and ground scraping ceremonies. Both parents participate in selecting and preparing the nest site, which is often a shallow depression scraped into the bare ground, sometimes lined with pebbles or other small objects for camouflage.
Once eggs are laid, both the male and female take turns incubating them, a period lasting approximately 22 to 28 days. Males often incubate at night, while females typically sit on the eggs during the day. After hatching, killdeer chicks are precocial, meaning they are born with open eyes, covered in downy feathers, and can walk and feed themselves almost immediately. Despite their independence in foraging, both parents continue to guard and guide the young, leading them to feeding areas and performing distraction displays, such as the well-known “broken-wing act,” to deter predators.
Factors Influencing Pair Bond Stability
Several factors can influence whether killdeer pairs reunite for subsequent breeding seasons. The success of the previous breeding season, particularly the successful fledging of young, is a factor. A successful breeding outcome might encourage a pair to re-establish their bond in the following year.
The availability and quality of breeding territory also influence pair reunion. If a territory proved suitable and productive, individuals, particularly males, may return to that specific area. The survival of both partners is another obvious factor; if one partner does not survive the non-breeding season, the remaining bird will seek a new mate.