The common cuckoo (Cuculus canorus) is a member of the cuckoo order of birds, Cuculiformes, which includes the roadrunners, the anis and the coucals. This species is a widespread summer migrant to Europe and Asia, and winters in Africa. It is a brood parasite, which means it lays eggs in the nests of other bird species, particularly of dunnocks, meadow pipits, and reed warblers. Although its eggs are larger than those of its hosts, the eggs in each type of host nest resemble the host's eggs. The adult too is a mimic, in its case of the sparrowhawk; since that species is a predator, the mimicry gives the female time to lay her eggs without being seen to do so.
Palearctic passage migrant, generally below 2000 m in Kenya. Mainly in se. Kenya, from October to December , more numerous in March and April (when sometimes common at coast). Scarce in north and east.
Source : Wikipedia / Birds of Kenya and Northern tanzania.