33 genera, see text Cuckoos are birds in the Cuculidae (/kjuːˈkjuːlɪdiː/ kew-KEW-lih-dee) family, the sole taxon in the order Cuculiformes (/kjuːˈkjuːlɪfɔːrmiːz/ kew-KEW-lih-for-meez).

Cuckoos have played a role in human culture for thousands of years, appearing in Greek mythology as sacred to the goddess Hera.

One of the most important distinguishing features of the family is the feet, which are zygodactyl, meaning that the two inner toes point forward and the two outer backward.

The New World ground cuckoos are similar to the Asian ground-cuckoos in being long legged and terrestrial, and includes the long-billed roadrunner, which can reach speeds of 30 km/h (19 mph) when chasing prey.

Amongst the Phaenicophaeinae, the malkohas and Asian ground cuckoos are restricted to southern Asia, the couas are endemic to Madagascar, and the yellowbill is widespread across Africa.

The majority of species occur in forests and woodland, principally in the evergreen rainforests of the tropics, where they are typically but not exclusively arboreal.

Species breeding at higher latitudes migrate to warmer climates during the winter due to food availability.

The long-tailed koel, which breeds in New Zealand, flies to its wintering grounds in Polynesia, Micronesia, and Melanesia, a feat described as "perhaps the most remarkable overwater migration of any land bird.

[12] Within Africa, 10 species make regular intracontinental migrations that are described as polarised; that is, they spend the nonbreeding season in the tropical centre of the continent and move north and south to breed in the more arid and open savannah and deserts.

Most cuckoos are insectivores, and in particular are specialised in eating larger insects and caterpillars, including noxious, hairy types avoided by other birds.

[16] Larger, ground types, such as coucals and roadrunners, also feed variously on snakes, lizards, small rodents, and other birds, which they bludgeon with their strong bills.

The parasitic koels and channel-billed cuckoo in particular consume mainly fruit when raised by frugivore hosts such as the Australasian figbird and pied currawong.

Nonparasitic cuckoos leave the nest before they can fly, and some New World species have the shortest incubation periods among birds.

The chick has no time to learn this behavior, nor does any parent stay around to teach it, so it must be an instinct passed on genetically.

[29] Since obligate brood parasites need to successfully trick their host for them to reproduce, they have evolved adaptations at several stages of breeding.

[35] In these cases, there is selective pressure on cuckoos to lessen their egg size to be a more effective mimic, but physiological constraints hinder the species from doing so.

[36] Since cuckoos in this situation can effectively parasitize despite laying eggs slightly larger than those of their hosts, there are little selective pressures to evolve "perfect" mimicry.

Daurian redstarts (Phoenicurus auroreus), another cuckoo host, lay clutches of either pink or blue eggs.

Experiments in the lab show similar findings: cuckoos parasitized artificial nests containing blue eggs more frequently than pink ones.

The researchers attributed this to a strong-smelling predator-repelling substance secreted by cuckoo chicks when attacked, and noted that the interactions were not necessarily simply parasitic or mutualistic.

The authors of the first study have responded to points made in the second [43] and both groups agree that further research is needed before the mutualistic effect can be considered proven.

The family Cuculidae was introduced by English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1819.

[48] A 2014 genome analysis by Erich Jarvis and collaborators found a clade of birds that contains the orders Cuculiformes (cuckoos), Musophagiformes (turacos), and Otidiformes (bustards).

It is from a 2005 study by Michael Sorenson and Robert Payne and is based solely on an analysis of mitochondrial DNA sequences.

[49] The number of species in each genus is taken from the list maintained by Frank Gill, Pamela Rasmussen and David Donsker on behalf of the International Ornithological Committee (IOC).

These numbers include two species that have become extinct in historical times: the snail-eating coua from Madagascar and the Saint Helena cuckoo which is placed in its own genus Nannococcyx.

[50] In Greek mythology, the god Zeus transformed himself into a cuckoo so that he could seduce the goddess Hera, to whom the bird was sacred.

[53] Three sacred cuckoos appear in the Finnish epic the Kalevala, connected to the death of a young girl who was being forced into marriage.

In England, William Shakespeare alludes to the common cuckoo's association with spring, and with cuckoldry, in the courtly springtime song in his play Love's Labours Lost.

[57] Additionally, the brood parasitism of some cuckoo species gave rise to the term "cuckold", referring to the husband of an adulterous wife.