Cuckoos lay their eggs in the nests belonging to other bird species.

The longer version

A female brood parasite lays her egg directly into another species' nest, usually removing one host egg at the same time so the clutch count looks unchanged. The egg often matches the host's eggs in colour and spotting, and the hatched chick frequently evicts the host's own young or simply outcompetes them for food.

The host ends up feeding a chick much larger than itself, driven by a begging call that is often exaggerated for the purpose. Hosts fight back by learning to recognise foreign eggs and abandoning or ejecting them, which drives a long arms race of better mimicry. Several bird families beyond cuckoos practise it.

Where this entry sits

Here you will find feathered trivia about flight, migration, nests, eggs, and the songs birds sing. Expect short surprising facts on penguins, owls, hummingbirds, and other familiar birds from gardens, forests, wetlands, and distant coastlines. The full list sits on the Birds page, where every entry is listed in order.