The bird, named Lee, spent two months in the New Zealand Center for Conservation Medicine at the Auckland Zoo, Stuff.com reported. Veterinarians said at first they were unsure if the bird would survive because he was so underweight.

"It's hugely pleasing to see Lee so healthy now," said Dr. John Potter. "He's put up with twice-daily tube feedings to enable us to get his weight up to more than 1.7 kilograms (between 3 and 4 pounds), and for a bird that's been held in captivity for the first time, he's really pretty chilled out."

Veterinarians say that none of the other kakapo on Anchor and Codfish islands appear to be having problems. They say that Lee may have swallowed a fishing weight or a piece of buckshot.

The kakapo, a Maori name meaning night parrot, are flightless birds. Once common throughout New Zealand, their numbers dropped because of hunting by the Maori and then habitat loss and predation by mammals introduced after European settlement. Only 91 birds are known to remain in the wild.