Although many species from several bird families show no parental care for their young, the cuckoos are undeniably the most famous for this behavior. The females of most, but not all, cuckoo species lay their eggs in the nests of other “host” species (a habit known as brood parasitism), forcing the latter to look after their offspring, and thereby avoiding all parental responsibilities! Most brood-parasitic cuckoos specialize on a small number of potential host species and employ several “tricks” to fool the host into accepting their eggs, such as removing one host egg before laying their own, and mimicking the egg coloration of the host. Although some hosts recognize and reject the alien egg, most accept and incubate it along with their own clutch. But when the cuckoo chick hatches, it destroys the hosts’ eggs or chicks by pushing them out of the nest, so that it receives all of the food brought by its “foster parents”.
Like parrots, the cuckoos are zygodactylous, having the outer and inner toes directed backwards and the other two toes directed forwards. Three groups of this family are represented in the Greater Sundas, most belonging to the true (brood-parasitic) cuckoos, which are arboreal (tree-dwelling) and characterized by slender bodies with long tails, pointed wings, short legs and relatively short, slightly decurved bills. The plumage of many of these birds, especially the aptly-named “hawk-cuckoos”, apparently mimics that of the predatory goshawks and sparrowhawks, and may function to frighten away host birds whilst the female lays its egg in the host’s nest. The same plumage in males probably protects them from such raptors while calling, typically from an exposed perch. In flight, both sexes can be easily confused with small raptors. They are insect-eaters, many species specializing on caterpillars, which they find by scanning the foliage during long periods of inactivity.
In contrast to the true cuckoos, the other two groups of this family (Malcohas and Coucals) build their own nests, and look after their own young. Larger than most true cuckoos, they have heavier bills and their diet includes small vertebrates (such as small birds) and fruit.
Some 23 species have been recorded in Java,
of which may be found in Baluran National Park.
Straight, with rapid wings beat similar with pigeons (true cuckoos).