53 Cuckoo egg Robin egg Non-stop production If conditions are good, a female blackbird can lay up to five clutches of four eggs in a season, although few offspring survive the winter. Cuckoo Cuckoos lay their small eggs in the nests of other birds. A cuckoo has tried to match the colour of its egg with those of a robin. On the ground The nocturnal nightjar lays its pair of eggs on rough ground. Hole-nester Many woodpeckers chisel out holes in trees for their glossy eggs. In the city The kestrel sometimes nests on city buildings, where its eggs perch on rooftops. Vulnerable hawks Sparrowhawks, like most birds of prey, lay eggs that can be camouflaged easily. The eggs are bright blue when laid, but the colour fades. Varied colours The fish-eating osprey produces eggs of varied colours. On rocky cliffs The Egyptian vulture lays its eggs high upon cliffs and in cave mouths. One of a pair Eagles leave several days between laying their first and second egg. Slow developers Buzzard eggs take over five weeks to be incubated. The young stay in the nest for a further six weeks. Cuckoo A female cuckoo can lay up to 23 eggs in other birds’ nests . Dunnock egg A poor match The European cuckoo has too many hosts to match all their eggs. Cuckoo egg American robin This bird is a member of the thrush family, unlike the European robin.