Common Cuckoo

The common cuckoo is a medium-sized migratory bird that breeds across much of Europe and Asia before wintering in Africa, best known for its distinctive two-note call, from which its name derives, and for its remarkable brood parasitism, in which the female lays her eggs in the nests of other, smaller bird species and leaves them to raise her young. Cuckoo chicks typically hatch earlier than the host's own eggs and instinctively push the host's eggs or chicks out of the nest, monopolizing the foster parents' feeding effort as they grow to a size often many times larger than the birds raising them. Different populations of common cuckoos tend to specialize in parasitizing particular host species, and female cuckoos often lay eggs that closely mimic the color and pattern of their chosen host's own eggs to avoid detection. The species has long fascinated naturalists and features prominently in folklore across Europe and Asia, though its population has declined in parts of its breeding range in recent decades.