The Killdeer, a widespread plover across North America, is distinct for its double black breast bands and loud, repetitive call. Unlike many other shorebirds, the Killdeer commonly inhabits open, dry environments far from large bodies of water, adapting well to human-modified landscapes. This adaptability extends to their nesting behavior. This article examines the Killdeer’s nesting cycle, focusing on the incubation period that determines how long they sit on their eggs.
The Killdeer Nest and Egg Characteristics
The Killdeer does not construct a traditional nest but utilizes a simple scrape on the ground, often in exposed locations like gravel driveways, cultivated fields, or flat, graveled rooftops. This depression is typically three to three-and-a-half inches across and may be lined with small materials like pebbles, shell fragments, sticks, or bits of trash collected by the parents after egg-laying begins. The choice of an open location, often with sparse vegetation, allows the incubating parent a clear view of approaching threats.
The eggs themselves are typically buff or beige and heavily marked with dark speckles, blotches, and scrawls of black and brown. This patterning helps them blend seamlessly into the sandy or gravelly substrate of the nest, offering passive protection from predators. A typical clutch consists of four eggs, though a pair may lay between two and six. These eggs are relatively large for the size of the adult bird.
The Incubation Period and Parental Roles
The incubation duration typically lasts between 24 and 28 days. This period begins once the full clutch has been laid, ensuring that all chicks hatch at roughly the same time despite the eggs being laid on successive days. Both the male and the female Killdeer share the duties of incubation, demonstrating a high degree of biparental care.
The division of labor often sees the male taking the night shift, while the female primarily incubates the eggs during the day. Because the nest is an open scrape on the ground, the parents must regulate the temperature of the developing embryos. In hot conditions, adults will shade the eggs and may even soak their belly feathers to cool the eggs through evaporative cooling. Conversely, they sit tightly on the eggs in colder weather, sometimes incubating them for as much as 99% of the time to maintain the necessary warmth.
A primary adaptation during this time is the “broken wing” display. When a predator or human approaches the nest, the adult bird runs away from the nest, dragging a wing as if injured, to draw the attention of the intruder away from the eggs. Once the threat is sufficiently distracted and lured away, the adult will suddenly recover and fly off, successfully diverting the danger from its offspring.
Post-Hatching and Precocial Young
The Killdeer young hatch in a highly advanced state known as “precocial.” This means the chicks are covered in soft down feathers, have their eyes open, and possess well-developed legs that allow for immediate mobility. Killdeer chicks are sometimes called “nest fugitives” because they leave the nest scrape shortly after their down dries, often within hours of hatching.
The young are capable of walking and feeding themselves almost immediately. Unlike the young of many other bird species, Killdeer parents do not bring food to the nest; instead, they lead the chicks to a suitable foraging area. The parents continue to protect and guide their young, brooding them frequently for warmth and shelter during the first couple of weeks. The chicks remain with their parents until they are capable of sustained flight, a process that typically takes around 20 to 31 days after hatching.