Breeding, nesting and migration
Although stone-curlews belong to the wading bird family, they are not usually seen near water, preferring inland dry stony ground.
Males usually return to within 9 miles (15 km) of their hatching site. In early spring the males’ eerie curlew-like calls can be heard at night near to their breeding grounds, hence the colloquial name “wailing heath chicken”.
During courtship, the male bird displays by walking with legs extended and head level with the body, sometimes with the tail cocked up like a wren. The female often follows. Neck arching and food offerings are also seen.
Birds are usually monogamous with pairs forming strong bonds before breeding. There have been some instances of males pairing with two females, usually switching during the breeding season.
Stone-curlews nest on open, bare ground within short, semi-natural grass heath or downland, and on arable fields, typically associated with chalky and sandy soils in the south and east of the UK, where they are at the most northerly point of their range.
The nest is a simple scrape, lined with small stones, shells, rabbit droppings or pieces of vegetation. Two medium-sized eggs are laid from April onwards, usually two days apart. They can range in colour from cream to buff with varying degrees of dark brown streaks or marks. Both sexes incubate, and chicks normally hatch after 26 days, leaving the nest within two days. Both parents bring food and remain with the chicks until they fledge at between 36 and 42 days.
Up to five replacement clutches can be laid if either the eggs or small chicks are lost, and nesting can continue into September. They are double-brooded but normally only one brood is now raised, possibly due to lack of available late nesting habitat. Second broods were once more common. Very occasionally, three broods are successfully raised to fledging.
Sensitivity to disturbance
Camouflage and secrecy are stone-curlews’ natural defences and nesting birds, eggs and chicks are all but invisible.
Adult birds can be disturbed by human presence as much as a third of a mile (500m) away, and have usually crept silently out of sight before being noticed. Chicks hide by lying flat and motionless on the ground. The main predator, particularly of nests and young, is foxes. When nesting on arable land, nests may fail due to accidental destruction by farm machinery or the crop becoming too tall and dense, unless they are protected.
After breeding and before their southbound migration, juveniles and adult birds gather together in roosts of up to a hundred or more individuals.
Stone-curlews gather into post-breeding roosts. In October and November, they start to leave for warmer climates in southern Spain and northern Africa where they will spend the winter. They usually return in mid March.
Occasionally, birds have been known to over-winter in the UK. French birds follow a similar pattern, but the species is also resident (non-migratory) in southern Europe and North Africa.
Stone-curlews are crepuscular (mainly active at night), when they feed on invertebrates such as ground beetles and worms.
They have large yellow eyes which point slightly downwards to help them hunt. For this reason they’ve also been nicknamed the “goggle-eyed plover”. They also occasionally take larger prey such as small rodents and chicks of other species.