19. Cuculigormes (Cuckoos)

The cuckoos are a family of birds, Cuculidae, the sole taxon in the order The cuckoos are generally medium-sized slender birds. The majority are arboreal, with a sizeable minority that are terrestrial. The family has a cosmopolitan distribution, with the majority of species being tropical. Some species are migratory. The cuckoos feed on insects, insect larvae and a variety of other animals, as well as fruit. Many species are brood parasites, laying their eggs in the nests of other species, but the majority of species raise their own young.

About 56 of the Old World species and 3 of the New World species (pheasant, pavonine, and striped) are brood parasites, laying their eggs in the nests of other birds. These species are obligate brood parasites, meaning that they only reproduce in this fashion. In addition to the above noted species, yet others sometimes engage in non-obligate brood parasitism, laying their eggs in the nests of members of their own species in addition to raising their own young. The best-known example is the European common cuckoo.