In New Zealand, the return of wild takahē populations marks a cautiously celebrated conservation victory, and the return of one of the world’s rarest creatures. The birds had been formally declared extinct in 1898, their already-reduced population devastated by the arrival of European settlers’ animal companions: stoats, cats, ferrets and rats. After their rediscovery in 1948, their numbers are now at about 500, growing at about 8% a year.