California condors were extinct in 1987 but have been reintroduced and now number a few hundred. Among the largest birds in the world, this strange bald-headed vulture briefly became extinct in the wild in 1987 due to poaching, poisoning, and habitat destruction (all exacerbated by its slow maturation rate). It was later reintroduced back into the wild thanks to one of the largest conservation efforts ever conceived, but it is still one of the rarest birds in the world with only a few hundred remaining.