The ultimate evolutionary freeloaders! Cuckoos and cowbirds have mastered the art of outsourcing parenthood by laying eggs in other birds' nests. Why build a nest, incubate eggs, and feed hungry chicks when you can trick some unsuspecting bird into doing all the work? It's like having a full-time nanny service without paying a single seed! Natural selection really said "work smarter not harder" with these birds. Their entire reproductive strategy is basically "here's my kid, good luck, I'm going on vacation!"