This is a long, very sad story
The reproductive strategy of cuckoos involves laying eggs in the nests of other bird species, leaving the foster parents to raise the young cuckoo. Cuckoo eggs often mimic the appearance of the host bird's eggs to avoid detection.
When the cuckoo chick hatches, it typically outcompetes the host bird's chicks for food, sometimes growing larger than its foster parents. This strategy, known as brood parasitism, allows cuckoos to invest less energy in parental care and allocate more resources to reproduction.