Concept:Birds build nests to lay their eggs and incubate their younger ones.Different birds build nests at different places, some on ground level, some high up on the tree.Different birds use different techniques and different materials to build their nests.Explanation:Cuckoo:A cuckoo bird never makes its nest.It lays its egg in the nest of a crow.This ensures that there's a higher chance of clutch formation. (The clutch is the number of eggs laid).The cuckoo's eggs resemble those of the crow in pattern and colour, which helps them in nesting.The cuckoo is a brood parasite which means it lays eggs on other birds' nest.Thus, the cuckoo bird never builds a nest.Additional Information The dove makes its nest among the thorns of a cactus plant or a Mehendi hedge.The sparrow and pigeon make their nest anywhere on top of a cupboard, behind a mirror, on a ledge.The barbet or coppersmith bird makes its nest in a hole, in a tree trunk.The tailorbird uses its sharp beak to make its nest by stitching together two leaves on a bush. It lays its eggs in the fold of the leaf that it has made.The sunbird makes a nest that hangs from the branch of a small tree or a bush.The robin makes its nest with soft twigs, roots, wool, hair and cotton wool at ground level, lower branches of a tree or sometimes at the top.