The most dangerous predators for baby alligators are adult alligators. They are easy pickings for adults and they eat them. Other than adult alligators, eagles, vultures, hawks and other reptiles too hunt baby alligators. Men with rifles or other trapping / killing / harvesting equipment.
In South america, anacondas and caimans eat herons. In North america, alligators, crocodiles, and eagles prey on herons and cranes. In africa, nile crocodiles and eagles prey on storks and cranes. In asia, saltwater crocodiles, mugger crocodiles, wolves, and eagles eat wading birds.