Birds with long, pointed wings and tail, and a slender body with a hooked, slender bill. True cuckoos are infamous brood parasites; they do not build their own nest but lay their eggs in the nests of other birds. Upon hatching, the young cuckoo throws out all other eggs in the nest. The host parents continue to feed their parasitic baby, even if it is much larger in size. Sunbirds, ioras, whistlers and fantails are some of the hosts for local cuckoos. Many resident species have loud, persistent calls which increase in tempo, giving rise to the name ‘brain fever bird’. Cuckoos eat mainly insects and are particularly fond of caterpillars, including hairy ones. Singapore has 14 species of cuckoos, of which half are migratory.