Which bird is known for brood parasitism?

The story behind the answer

Cuckoo is correct because many cuckoo species practice brood parasitism—laying their eggs in the nests of other birds (like robins or warblers). The cuckoo chick often hatches early, may push out the host’s eggs or chicks, and monopolizes food while the unsuspecting hosts raise it as their own. Cuckoos even evolve eggs that closely mimic the host’s egg color and pattern to avoid detection.

This strategy drives a coevolutionary “arms race”: hosts evolve better egg recognition, while cuckoos refine their mimicry. Other brood parasites include cowbirds and honeyguides, but the cuckoo is the classic example. Memory tip: “Cuckoos ‘outsource’ parenting”—just like a cuckoo clock keeps time for you, cuckoos let other birds do the hard work.