Small to medium-sized long-tailed, long-winged, long-tailed, parasitic, largely migratory birds. They are unobtrusive, skulking in thick cover, but may have loud, far-carrying and monotonous calls.
Some cuckoos specialise in eating hairy caterpillars that are avoided by most other birds.
All are brood parasitic, each subspecies specializing on one or a small set of hosts and laying 1 - 3 eggs per host nest. They can lay eggs very quickly (a few seconds). Most subspecies have evolved eggs that closely mimic the hosts. In cuckoos with multiple hosts, separate female groups (called gentes singular gens) specialize on particular hosts. In Cuculus, Chrysococcyx and Pachycoccyx cuckoos, the parasite chick ejects host eggs or chicks from the nest, whereas Clamator cuckoos do not, although the parasite chick may smother and trample the host chicks.

Chrysococcyx = golden cuckoo (in reference to iridescent feathers
Clamator = noisy (in reference to chattering calls)
Cuculus = a cuckoo

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