Superb Fairy-wren

Superb fairy-wrens teach their offspring before hatching. Incubating mothers sing a specific call to eggs during the final incubation week. After hatching, chicks incorporate elements of this 'password' call into their begging calls. Mothers preferentially feed chicks whose begging matches the prenatal password, discriminating against brood parasites (cuckoos) who never heard the password.

The password system represents prenatal education. Embryos learn acoustic patterns through the eggshell and encode this learning into post-hatching behavior. This isn't instinct—cross-fostering experiments show chicks learn whatever password they heard during incubation, not a genetically specified call. Learning happens before birth.

Anti-parasite function drives the behavior. Horsfield's bronze-cuckoos parasitize fairy-wren nests, laying eggs that hatch before host eggs. Without the password system, cuckoo chicks would monopolize parental care. The prenatal password acts as authentication—only offspring who heard the incubation call can prove their identity.

Males learn the password too. Fathers who hear the incubation call update their feeding preferences to match the password. This family-wide authentication creates a coordinated defense against parasitism.

For organizations, fairy-wrens demonstrate that onboarding can begin before formal entry. Prenatal cultural exposure—internships, pre-hiring engagement—creates authentication mechanisms that distinguish insiders from outsiders. Early exposure to organizational 'passwords' accelerates integration.