Double-striped Thick-knee

The Double-striped Thick-knee is a medium-sized bird, approximately 46 to 50 centimeters in length. Its most distinctive field mark is the prominent double stripe above and below the eye, which gives it a perpetually alert appearance. The plumage is predominantly brownish-gray, with intricate patterns that provide excellent camouflage against the dry grasslands. The bird's long, pale yellow legs aid in its identification, especially when it's in motion. Juvenile Double-striped Thick-knees resemble adults but have slightly less defined patterns and a more buffy appearance. There is little sexual dimorphism, meaning males and females look quite similar. In flight, the bird's broad wings and slow, deliberate wingbeats are characteristic, with a white band across the wings visible in flight. The Double-striped Thick-knee typically assumes a horizontal posture when perching, blending seamlessly into its surroundings. Compared to similar species like the Peruvian Thick-knee, the Double-striped has more defined facial stripes and a more robust build.

The Double-striped Thick-knee is an opportunistic feeder, primarily consuming insects and small invertebrates. Its diet includes beetles, grasshoppers, and ants, which it forages for by walking slowly and methodically through grasslands. The bird uses its keen eyesight to detect prey, often catching insects in its powerful beak. When larger prey like small mammals or reptiles are available, the bird may also attempt to capture these. Seasonal changes can influence the Double-striped Thick-knee's diet, with a shift towards more plant material, such as seeds and fruits, during times of insect scarcity. Its feeding schedule is predominantly nocturnal, aligning with its overall behavior pattern.

The Double-striped Thick-knee exhibits solitary or small group behaviors, often seen in pairs or family groups. It is highly territorial during the breeding season, with pairs defending their chosen nesting area aggressively against intruders. Courtship involves displays that include bowing and calling, which strengthen pair bonds. During non-breeding periods, the bird may be more tolerant of conspecifics, occasionally forming loose flocks. Its response to predators includes freezing and relying on its cryptic plumage for concealment. The bird's daily activities revolve around rest during the day and feeding at night, though it may be active at dawn and dusk. Vocalizations play a significant role in territory defense and communication, especially during the breeding season.

The Double-striped Thick-knee nests on the ground, often choosing a site with sparse vegetation that provides some cover while allowing clear visibility of the surroundings. The nest is a simple scrape in the ground, sometimes lined with small stones or plant material. Females typically lay two to three eggs per clutch, which are well-camouflaged with speckled patterns that blend with the ground. Both parents participate in incubation, which lasts about 24 to 26 days. After hatching, the young are precocial, leaving the nest quickly but remaining under parental care for several weeks. The parents actively defend their offspring from predators, using distraction displays to draw threats away from the young. The Double-striped Thick-knee usually raises one brood per year.

The primary song of the Double-striped Thick-knee is a series of high-pitched whistles, often described as mournful or plaintive. These calls can carry over long distances, particularly at night when the bird is most vocal. The call notes serve multiple purposes, from signaling territory ownership to maintaining contact with mates. Alarm calls differ slightly, being more abrupt and staccato, alerting others to potential danger. During the dawn chorus, the bird's calls are particularly prominent, adding to the symphony of sounds in its habitat. The calls are often compared to those of other thick-knees, maintaining a distinct, recognizable quality.

• 1The Double-striped Thick-knee has a unique adaptation: its knees are not double-jointed, but rather the 'knee' is actually an ankle joint.
• 2Despite their large eyes, Double-striped Thick-knees rely primarily on hearing to detect prey movements at night.
• 3The bird's camouflage is so effective that it can remain unseen even when in plain sight, blending seamlessly with arid landscapes.
• 4Double-striped Thick-knees are known for their peculiar habit of running short distances rather than flying when disturbed.
• 5A group of Double-striped Thick-knees is sometimes called a 'crash,' a nod to their cryptic nature and sudden appearances.
• 6This species can survive in surprisingly arid conditions, often found in areas with less than 500 millimeters of annual rainfall.
• 7The Double-striped Thick-knee's call has been likened to that of a distant curlew, adding to its mystique during nighttime hours.

The Double-striped Thick-knee is currently listed as Least Concern by the IUCN, with stable population trends across much of its range. However, habitat destruction, particularly in the form of agricultural expansion and urban development, poses significant threats. Conservation efforts focus on habitat preservation, emphasizing the protection of grassland and savanna ecosystems. Historical population changes have been relatively stable, though localized declines are noted in areas with significant habitat alteration. Continued monitoring and protection of open spaces are crucial for ensuring the species' long-term survival.