Thick-knee (Stone-curlew) (family Burhinidae)

BirdNocturnalCamouflage

Overview

Thick-knees (family Burhinidae), several of which are called stone-curlews, are medium-sized, cryptically coloured ground birds of open and semi-open country across warmer parts of the world. Their most arresting feature is a pair of large, staring yellow eyes — an adaptation for a largely nocturnal life — set in a streaky brown-and-buff plumage that makes them almost vanish against bare ground and stones. The odd name comes from the prominent, knobbly-looking joints in their legs.

Thick-knees are masters of camouflage and stillness by day, and they come alive at dusk and night, when their wild, wailing, curlew-like calls ring across the darkness — giving the stone-curlews their name despite not being true curlews.

Note: “thick-knee” covers a family of species; details here describe the group broadly. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Thick-knees live in open, often dry habitats across Africa, Europe, Asia, Australia, and the Americas — grassland, semi-desert, scrub, stony ground, riverbanks and shingle, and increasingly farmland — generally favouring bare or sparsely vegetated ground where their camouflage works best. Some species are tied to rivers and beaches, others to dry plains.

Diet

Thick-knees are carnivores that feed mainly on invertebrates — insects, worms, snails, crustaceans, and the like — and also take small vertebrates such as lizards, rodents, and frogs. They forage mostly at night, walking deliberately and watching with their big eyes, then darting forward to seize prey, much in the manner of a plover.

Behavior

By day, thick-knees rely on camouflage and stillness: they crouch or stand motionless on open ground, their streaky plumage and habit of freezing making them remarkably hard to spot, and they may flatten themselves or sneak away rather than flush. Their large eyes equip them for foraging in low light, and they are most active at dusk and through the night, when pairs and groups give loud, eerie, wailing calls. They nest on the ground in a simple scrape, and the well-camouflaged eggs and chicks are guarded by attentive parents that may use distraction displays against intruders. The knobbly leg joints that give them their name are actually the ankle (the “heel”), not a true knee.

Human Interaction & Conservation

Thick-knees are intriguing, harmless birds appreciated by birdwatchers for their cryptic looks and haunting night calls, and some live close to people on farmland and even in towns. As ground-nesters of open habitats, they can be vulnerable to habitat loss, disturbance, predation by introduced animals, and farming practices, and certain species are of conservation concern while others remain common. Consult the IUCN Red List for species-specific status.

More photos of the thick-knee (stone-curlew)