The Killdeer (Charadrius vociferus) is a familiar North American shorebird, recognized widely not for its proximity to oceans, but for its presence in open fields and lawns. This plover species is easily identified by the two black bands across its white chest and its loud, piercing call, which sounds like its common name. The Killdeer’s success across a broad range of habitats is largely attributed to its specialized diet, which centers almost entirely on invertebrates. This dietary focus allows the bird to thrive in areas far removed from traditional shorelines.
Primary Invertebrate Prey
The Killdeer is an insectivorous bird, with animal matter constituting a vast majority of its nutritional intake, sometimes as much as 98% of its diet. They actively seek out a variety of small, soft-bodied creatures found on the surface or just beneath the soil. A primary food source includes earthworms, which are particularly abundant in the moist soils of lawns and agricultural fields.
The bird’s diet also includes an extensive array of insects and their larval stages, providing a consistent supply of protein throughout the year. Specific prey items often consumed are beetles, grasshoppers, and insect larvae known as grubs, which they extract from the ground with their pointed bills. They are opportunistic feeders, also consuming spiders, centipedes, and snails when encountered on the ground’s surface.
In contrast to many other bird species that rely on seeds or grains, the Killdeer’s specialization on invertebrates distinguishes it as a dedicated ground predator. The ability to consume various life stages of insects, such as caterpillars and fly larvae, ensures a stable food supply across different seasons. Killdeer also occasionally consume small crustaceans, like crayfish, and aquatic insect larvae when foraging near water margins.
Distinctive Foraging Techniques
The Killdeer employs a methodical hunting strategy to locate and capture prey on open ground. This behavior is characterized by the “run-stop-look” technique, where the bird dashes forward quickly, then halts abruptly to scan the immediate area. They are highly visual hunters, relying on keen eyesight to detect the slightest movement of insects or worms.
The bird’s long legs allow for rapid bursts of speed, which are followed by a stationary posture that often involves a characteristic head-bobbing motion. This pausing allows the Killdeer to process visual cues and vibrations created by subsurface prey. When an item is spotted, the bird uses its stout bill to quickly peck or probe the ground.
A specialized method involves a behavior called “foot-trembling” or “foot-paddling.” The Killdeer stands on one leg and rapidly vibrates the other foot on the substrate, sending small tremors into the soil or shallow water. This vibration encourages earthworms and grubs to move closer to the surface for capture.
Environmental Factors Shaping the Diet
The specific composition of the Killdeer’s diet is highly dependent on the type of open habitat in which it forages. Their adaptability to human-altered landscapes means their menu changes based on local availability, from urban parks to agricultural land. In heavily cultivated areas, such as newly plowed fields, the diet leans heavily toward subsurface prey like grubs and earthworms exposed by the machinery.
Killdeer frequently forage in short-mown areas like golf courses and large lawns, consuming surface-dwelling insects and earthworms. Conversely, when foraging near freshwater edges, mudflats, or riverbanks, they incorporate aquatic sources into their meals. These locations provide access to small crustaceans and aquatic insect larvae.
The Killdeer’s willingness to inhabit diverse environments, including parking lots and gravel rooftops, ensures a consistent supply of invertebrates, even if the specific species of prey must change. Their flexibility in habitat use allows them to exploit a wide range of micro-environments, ensuring that they can always find sufficient animal matter.