This is just one example of juvenile parasitism, an evolutionary strategy.

This is but one example of brood parasitism, an evolutionary strategy in which one animal tricks another into rearing its young. It’s especially well-known among birds. By depositing their eggs into a stranger’s nest, brood parasites are able to shift the major costs of parenting onto others. Brood parasite chicks usually hatch early, then monopolize their host parents’ attention. Some stab their fellow nestlings to death, while others shove the remaining occupants out of the nest. Meanwhile, others are less harmful to their hosts. Not all brood parasites kill all of their host’s offspring outright.