Does a cuckoo know it's a cuckoo?

ABSURD LITTLE BIRDS ACROSS THE world lay their eggs in the nests of other species, leaving the hapless parents to raise a changeling at the expense of their own offspring.

- Richard Pallardy

The majority are cuckoos — of the 150 Cuculidae species, 64 are brood parasites. Brood parasitism has evolved multiple times, testifying to its utility as an evolutionary strategy. A range of other birds also engage in this sneaky behaviour, from honeyguides to cowbirds and even one species of duck.

Most birds that foist their young off on other species have no alternative - they simply do not know how to care for them. Their genetic programming seems to have deleted the impulse to build a nest or incubate an egg or bring food to a voracious nestling. They would not have survived were their manipulations ineffective.